KR950014418B1 - Bodies with reduced base drag - Google Patents

Abstract

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Description

Object with reduced base drag

FIG. 1 shows the fluid dynamics associated with a blunt body moving with respect to fluid flow.

2 is a perspective view of a blunt object using the features of the present invention.

3 is a sectional view taken along line 3-3 of FIG.

4 is generally taken in the direction of line 4-4 of FIG.

5 is a cross-sectional view generally taken in the direction of line 5-5 of FIG.

6 is an enlarged view of the area indicated by Y in FIG.

7 is a perspective view of a vehicle using the present invention.

8 is a rear view of the motor vehicle generally taken in the direction of line 8-8 of FIG.

9 is a partial cross sectional view taken along line 9-9 of FIG.

10 is a side view of a tractor trailer using the present invention.

11 is a rear view of a tractor trailer generally taken in the direction of line 11-11 of FIG.

12 is a partial perspective view of a body having a blunt end using another embodiment of the present invention.

13 is a sectional view taken along line 13-13 of FIG.

14 is a rear view taken in the direction of line 14-14 of FIG.

15 is a side view of the projectile using the present invention.

FIG. 16 is a rear view of the projectile of FIG. 15 taken generally in the direction of line 16-16 of FIG.

17 is a partial perspective view of an airfoil (alrfoil) using the present invention at the rear of the wing.

FIG. 18 is a view taken generally in the direction of line 18-l8 of FIG.

19 is generally taken in the direction of line 19-19 of FIG. 18;

20 is a perspective view of an airfoil showing another embodiment of the present invention.

21 is a perspective view of "wings" according to the prior art.

FIG. 22 is a cross sectional view taken along line 22-22 of FIG. 21 of the prior art;

FIG. 23 is a cross sectional view taken along line 23-23 of FIG. 21 of the prior art;

* Explanation of symbols for main parts of the drawings

16: downstream 28: wired

20: blunt end surface 22: upper edge

24: lower edge 36: upstream direction

40: goal 43: goal entrance

45: valley part 46: side wall surface

48: side corner 300: casing

302: shell case 304: the end of the shell case

306: casing surface, 402: high pressure surface,

404: low pressure surface, 406: posterior wing.

The present invention is directed to reducing base drag.

Drag is the result of viscous effects, in particular surface bubbles and surface pressure changes due to separation or separation bubbles, and drag is caused by viscous effects, in particular separation bubbles or separation zones (low pressure zones). And as a result of surface pressure changes. Separation zones occur when two- or three-dimensional boundary layers deviate from the surface of the body. The angled or blunt body is shaped to promote a sharp downstream pressure gradient in the streamline that flows around the body, which can separate the flow from the surface. This is especially true for bodies with blunt end faces, such as car and tractor trailers, and projectiles with blunt ends. As these objects pass through the air, the separator bubble behind the object creates a high base drag.

Airfoil bodies, such as aircraft wings, rudders, sails, and rotor blades and stator wings of gas turbines, have a streamlined shape that avoids the separation of two-dimensional boundary layers in the flow direction across the entire surface at an appropriate angle of attack (about 15 ° or less). Have At larger angles of attack (or increased load), separation occurs, circulating flow zones (or low pressure wakes), which greatly increase drag and reduce lift. As used in this specification and the appended claims, "separating two-dimensional boundary layers in the flow direction" means that the fluid separates from the surface of the body and eventually creates a flow near the wall that moves in the opposite direction to the flow of the fluid.

Reducing drag and improving (if appropriate) the Stall Characteristics in the body lying in lift and fluid flows are a constant goal of aerodynamics. To avoid boundary layer separation in airfoils (or other streamlined bodies) or to minimize the separation occurring downstream along the surface of the airfoil in order to minimize possible drag, the surface along the length of the airfoil in the direction of fluid flow By creating a contour it reduces the pressure rise in the downstream direction.

Another well-known method for reducing drag in airfoils is to create an exchange at the boundary layer by delaying the separation point to give the Ducorn mean momentum of the boundary layer fluid, which is further downstream along the surface against the back pressure sphere. For example, US Pat. No. 4,455,045 describes an elongated and expanded channel on the flow surface. This channel has sharp longitudinal edges. A boundary worm on the surface flows into this channel and creates a directional vortex below the normal flow surface, which activates the flow in the channel to sustain the adhesion of the boundary layer along the channel floor.

Similarly, stephens created a number of adjoining flow channels in the flow surface that extend laterally from the narrow inlet to the wide outlet. In general, triangular lamps are formed between adjacent channels. Stevens explains that this boundary layer flow diverges between the ramp and the channel. The flow between these channels spreads and the boundary layer becomes thinner and stays longer on the surface. This ramp flow is converted to normal flow. One application (Fig. 6 of Stevens) was made between the roof of the car and the rear window in order for the flow to continue on the surface over a greater distance than normal.

In US Pat. No. 1,773,280, the installation of floors extending from the front of the wing to the rear of the wing, along the top of the wing, along the top of the wing, increased lift without increasing drag on the aircraft wing. Peaks These floors have an airfoil shape when viewed from the arm and are rapper to some point behind the wing. This concept does not take into account the viscosity that causes boundary layer separation and therefore cannot be expected to avoid separation under high lift conditions.

U.S. Patent No. 3,588,005 discloses "air to accelerate the separation by providing an energy channel to the boundary layer and providing a channel of accelerated flow in the direction of free flow to continue laminar flow in the region of normal reverse pressure gradients." Use floors extending in the chord direction on the top surface of the foil. These floors protrude from the surface "up to the height of the boundary layer". The cross flow component is "accumulated over the floor and gives the body a" corkscrew "flow from the tail end rather than encountering a sudden reverse force gradient in the free flow direction created by the blunt tail end. With respect to the floors of US Pat. No. 1,773,280 discussed above, the flow is also accelerated between the floors to allow for more sustained laminar flow across the airfoil surface.

U.S. Patent Nos. 3,741,235 and 3,578,264 use a series of block or concave shapes extending generally transverse to the flow direction to create a vortex to delay separation. It is suggested here that the maximum height of the convex or concave shape should be less than the thickness of the boundary layer.

"Reduction of drag due to rear flap of wings" by DL Whltehead, M kodz and PM Hield and published by the University of Canbridge in 1982. In this burned paper, drag due to blunt wings (50,8 cm wide, 50.8 cm long, 3 81 cm thick, with blunt wings posterior) and blunt wing backs, resulted in flow and troughs extending the last 17.78 cm of the length of the freezing direction. Wrinkles) are formed alternately and reduced. This vane canal and the cross section in the upstream direction across the corrugation have a sinusoidal wave length of 20,32 cm, although the thickness of the wing ash is from 5.08 cm up to 0 upstream from the rear of the wing, although the depth of bone or floor height (amplitude) Vary, but remain constant over the length of each valley and floor. The total valley exit area is more than 50% of the blunt area. 21-23 show the wings described herein and have a size given by the unit length "a" It can be seen that the base drag of about one third is reduced when compared to a wing without wrinkles. Vortex in the wing width direction, which is alternately distributed from the top and bottom edges of the wing without wrinkles, is removed by the wrinkles.

It is generally believed that in the prior art split delay device there was considerable drag at steady state and therefore there was little benefit this delay device could give. This sometimes limits utility. Although many devices of the prior art have been proven to reduce drag, more advanced improvements are still needed, such as reducing base drag in blunt objects.

It is an object of the present invention to reduce drag in a bluntly finished body.

Another object of the present invention is to reduce the size of the downstream flow of the separator bubble of the bluntly finished body. In accordance with the present invention, an object placed in a fluid flow moving downstream with respect to the object has a surface extending in the downstream direction that ends with a blunt and generally downstream surface, where a plurality of valleys are disposed on the surface extending downstream and at the end surface To the blunt end surface in the direction of the fluid flow forming the bone outlet and to the blunt end surface in the direction of the fluid flow forming the bone outlet and the bone completes the flow and into the space immediately behind the blunt end surface. It is manufactured and designed to reduce the size of the separator bubble formed by flowing. In other words, the present invention reduces the strength of the low pressure zone formed just behind the blunt end surface.

In a seam, the blunt end surface of an object usually ends suddenly in the flow direction, such as when the downstream end surface or end surface is essentially perpendicular to the flow direction surface formed by the sharp curvature of the surface extending in the flow direction. Where it can be the end surface in the downstream direction. The bone of the present invention must be inclined or shaped to flow completely (without the two-dimensional boundary layer separation in the flow direction occurring between the bones) and therefore the bone must extend from one point upstream where boundary layer separation normally occurs. The bones are smoothly curved to form a u-curve to minimize losses in the cross-section cut vertically in one direction (there are no sharp angles where the sidewall surface of the bone meets the valley bottom). It forms a waved surface, which forms a wave in the cross section modified downstream.

U.S. Patent No. 857,907, co-owned by Wilter M Presz, Jr. and filed on April 30, 1986, entitled "Airfoil Body," forms a wavy thin wing backside. A description is given of a pneumatic Nil opening posterior wing with valleys and floors in the flow direction. On one surface, the valley makes a floor on the opposite surface. The skull and ridges provide a three-dimensional relief for low cloud volume boundary layer flows, thus preventing or delaying the enormous effects of two-dimensional boundary layer separation at the low pressure side of the airfoil. However, the present invention allows to reduce the base drag created behind a blunt object. The difference between US Pat. No. 857,907 and the present invention is that the bone in the present invention only needs to be formed on one surface. In addition, the bone can have a significant effect even when the blunt end surface area is more than 20 times larger than the pubic outlet area.

The weaning body leaves the bone in the direction of the momentum that causes this fluid to enter the stagnation zone behind the blunt end surface normally over the blunt end surface. It is thought that a down wash occurs. In addition, each valley is thought to create one large axial vortex from each sidewall surface at the exit of the goal, where large means that the whirlpool has a diameter about the depth of the bone. It creates a flow fleld that rotates in the direction and moves fluid from the bone and also near the fluid into the area behind the blunt surface. The net effect of this phenomenon, or combined with the downwash effect, is to reduce the base drag by reducing the size of the stagnant bubbles normally occurring behind the blunt end surface. In addition, if the vortex dispersion in the wing width assists in forming the base drag, the bone is thought to prevent this dispersion.

Adjacent valleys should be sufficiently spaced apart from each other such that there is sufficient space for the opposite vortex to develop fully from these sidewall surfaces. If the bones are too dense with one another, the rotating whirlpools will hinder or extinguish one another.

According to another aspect of the invention the fluid leaves from each bone with the smallest possible lateral component of velocity in order to minimize the second flow loss. For this reason it is preferred that the sidewalls of the valleys at a considerable distance upstream of the outlet are parallel to the direction of fluid flow adjacent to the surface near the bone.

According to another aspect of the invention it is preferred that the side wall of the bone at the outlet is steep and generally perpendicular to the surface extending in the flow direction. This is thought to increase the strength of the vortex generated by the sidewalls. As used herein and in the appended claims, the term "steep" means that the lines that intersect the steepest point on each sidewall in the cross section perpendicular to the bone length direction intersect to create an angle of only l20.

The present invention is particularly suitable for use in a body having a surface that is generally opposite to each other and meets a blunt downstream end surface perpendicular to the flow direction and extends in the downstream or flow direction. In this case, a plurality of downstream bones may be molded into both surfaces facing away from each other with a bone exit on the blunt end surface. Regardless of whether the valleys form one or two surfaces, they must have a depth at the exit and a sufficient cross-sectional flow zone relative to the overall area of the blunt end surface in order to have a significant effect on the normally occurring separation bubble. A minimum valley exit depth of only a few% of the distance between the surfaces facing away from each other at the valley exit may be effective. On each surface, the bone may have a bone corresponding to the opposite position to the bone on the opposite surface (symmetrical bone exit), or the bone outlet may alternate sideways along the transverse length of the end surface. Each of the opposite heads creates an opposite fluid flow across the blunt end surface. If the opposite facing surfaces are close to each other and flow flows from the valleys, an asymmetric type is preferred because the intra- and intra-wash sections of upwash and downwash reinforce each other.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments as shown in the accompanying drawings.

FIG. 1 shows what happens when fluid flows on the surface of an object ending with a blunt downstream end. The body in this figure is indicated by reference number 10 and has a smooth flat top face 12 and bottom face 14 through which the fluid flows. The wide arrow 16 indicates the downstream direction while the line 18 represents the streamline of fluid flowing adjacent to the surfaces 12 and 14. As is well known in the art, the fluid may stay affixed to the smooth surfaces 12 and 14 under a wide range of situations, but when the fluid reaches the blunt end surface 20 it cannot lift the corners and eventually the top edge 22 and Separation occurs at or near the lower edge 24. Flows leaving the upper and lower surfaces meet each other at some point in the downstream direction of the surface 20. Upstream of this there is a low pressure zone 21 (or “separating bubble”) downstream of the blunt end face 20 and between the upper and downstream streamlines if the fluid flows upstream of the body 10 through the emulsion. If so, this low pressure stagnation zone is a force in the downstream direction that resists any force that moves the object in the upstream direction. This force is referred to as the base drag and can be effective.

The present invention minimizes other losses as opposed to the benefit of a reduced basedrag and reduces the basedrag. The present invention has been shown and described schematically with respect to FIGS. 2 to 6. As shown in FIG. 2, an object using the present invention is generally indicated by a number 30. This object has an upper surface 32 and a lower surface 34. The foreign body is generally assumed to be moving through an airlike fluid in the upstream direction indicated by arrow 36. The downstream direction is indicated by arrow 38. In accordance with the present invention a plurality of downstream valleys 40 are formed in the upper surface 32 and a plurality of downstream valleys 42 are formed in the lower surface 34. The skull is generally μ-shaped in cross section perpendicular to the downstream direction. Each valley extending from the inlet 43 to the blunt end surface 44 meets the upper surface 32 and the lower surface 34 and generally flows downstream.

These bones should be sized and shaped to ensure that the flow is complete over its entire length, as no boundary layer separation in the flow direction occurs between the bones. In this respect, the fluid flowing along surfaces 32 and 34 must adhere to these surfaces as they enter through the inlet (without separation of borderworms in the flow direction). The tibial outlet 45 at the end surface 44 has a width or depth A (FIG. 6). The bones are zero-depth at the upstream end and gently blend into the upper and lower surfaces along the upstream end and its length. In this preferred embodiment each valley is increased in depth from the upstream end to the exit. However, this is not necessary. For example, this depth may be maximum upstream of the goal exit and remain constant up to the exit.

The bones in this embodiment have a smooth U-shape along its length in a cross section perpendicular to the downstream direction and have a smooth corrugated surface that is corrugated in the cross section perpendicular to the downstream direction. The side wall surface 46 is generally in the direction of the fluid flowing over the surface laid over a continuous portion of the bone length such that each valley has a pair of side walls facing the side edge 48 of the bone outlet 45. Parallel to and have a bone outlet. The parallel end characteristic of this sidewall surface 48 is best shown in FIG. Splitting the sidewalls is undesirable because it helps flow separation between all phases and results in lateral velocity components of the fluid leaving the bone, which creates an undesirable second flow loss.

It is believed that there are two other hydrodynamic mechanisms due to the reduced base drag resulting from the present invention, but these mechanisms are not fully understood. For example, the fluid leaving the bone enters the space immediately adjacent to the blunt end surface and into the space immediately behind it. It is thought that the fluid remains attached to the blunt end surface of the object after leaving the bone. Secondly, each bone creates a pair of large axial vortices, which are thought to be downstream. Each vortex is generated from each one of the two valley side edges 48. The pair of vortices rotates in opposite directions. These vortices create a flow field that moves the fluid from near the bone and fluid into the area behind the blunt surface and into the area adjacent to it.

The vortex from the lateral edges of one exit needs to be spaced a sufficient distance away from each other so as not to be interrupted by the interacting whirlpools from the lateral edges of the next adjacent bone. Thus, a portion of the blunt end surface 44 needs to extend laterally from the lateral edge 48 of each bone outlet to the lateral edge 48 of the adjacent bone outlet over the entire length of each side edge. This blunt end surface area is indicated by the hatched area of FIG. 6, located between the lateral edges of the bone indicated by reference numbers (48A) and (48B). In general, the region 50 projected in the downstream direction between the lateral edges of adjacent valleys should be at least about one quarter of the exit projected in the downstream direction of the valley.

It is believed that the best results are obtained when the sidewall surface 48 is steep at the exit. In the cross section perpendicular to the downstream direction, the downstream direction is the bone length direction and the line 53 tangent to the steepest point along the side edge 48 should form an angle of less than about 120 °. The smaller each 0 °, the better. The skull should have a sufficiently large cross section projected downstream from its exit as compared to the area projected in the entire downstream direction of the blunt end surface affecting the base drag. In some cases, only a few percent of the total blister area can produce a moderate base drag reduction. In most cases, less than 30% of the bone exit area of the entire blunt area will be used due to practical considerations.

It is also contemplated that the owl should not be too narrow for its depth and that the proper flow between the bones will not develop the base drag and no desirable base drag reduction will occur.

With respect to Fig. 6, the width of the valley at the exit is the maximum at the peak waveform length P and the valley depth at the exit is the maximum at the peak waveform width A. This ratio P / A should be greater than about 0.25 and is preferably at least 0.5. In addition, the ratio P / A should be less than about 4.0.

If the bone is too long for the outlet depth, the result is that the proper flow field between the bones will weaken before reaching the outlet and no effective results will be obtained. The ratio of bone length to exit width should be less than about 12 to 1.0.

In FIGS. 2-6 the end surface 44 is flat and perpendicular to the downstream direction, but the invention can be applied to other forms of blunt ends (FIGS. 12-14).

A valley shape similar to that shown in FIGS. 7 through 9 in FIGS. 7 through 9 was used at the rear end of the vehicle indicated by reference numeral 100. The bone 101 was formed in the upper trunk face 102 and the lower trunk face 104 of the vehicle. The skull intersects the blunt end surface 106 facing backwards. One difference between the embodiment of FIGS. 7 to 9 and the embodiment of FIGS. 2 to 6 is that the valleys 101 have protrusions 110 attached to the original vehicle outlines indicated by lines l12 and 114. Formed.

As a test, a 1/25 scale model of the Pontiac Fireblrd Tra11s-Am was purchased, and bones were cut and glued to the car's trunk lid and lower surface. This, in turn, adds an extra blocky area to the car. The base of each bone has a similar shape to the original surface of the vehicle. The total size of the blunt end surface with respect to FIGS. 8 and 9 is H = 3.56 cm and W = 7.37 cm. The bone length is 3 56 cm. The skull has a smoothly corrugated surface that is corrugated in a cross section perpendicular to the downstream direction. The corrugations have a period of 1.52 cm and apical width of 0.76 cm. The angle corresponding to the angle C of FIG. 6 is 90 degrees. Surfaces 112 and 114 are each formed at an angle of about 12 ° with the horizontal plane.

In the Wlnd tunnel test at a speed of 22.86 m / sec, the modified model using the present invention has a total drag of 16% less than the total drag generated in the conventional model, although the surface increases approximately 12.5%. Since only the rear end of the vehicle is deformed, the overall drag reduction can be thought of as a result of reduced base drag.

10 and 11 illustrate the present invention applied to a trailer truck, indicated at 150. The valleys 152 are recessed in the flat top and bottom surfaces and side surfaces of the trailer. The bone outlet 154 is on the blunt posterior end surface 156 and forms a smooth waveform along the four corners of the end surface 156. The ear bones are concavely shaped but can be formed by pasting the material onto the trailer surface as in the motor vehicle 100 shown in FIGS.

Another embodiment of the invention is shown in FIGS. 12-14. Note that the bone 200 is only on one surface here. The bone also has a smooth, flat drawing 104 and a relatively sharp edge 202 in which the bone is semicircular in cross section at all points along its length. Although sharp edges are not desirable, significant edge benefits can still be obtained in this shape because these edges reduce losses. As best seen in FIG. 13, the bottom surface 206 of the bone is gently connected to the surface 204 at the upstream end 205 of the bone and has an outlet 210 at the curved blunt end surface 209. This outlet 210 is located upstream of where boundary layer separation occurs from the surface 204 (where there is no bone). As discussed with respect to the embodiments of FIGS. 2-6, the projection portion in the downstream direction of the blunt surface portion 211 (hatched) positioned laterally between the pair of adjacent valleys is at least one of the areas projected downstream of the bone outlet. You must have an area equal to / 4.

The bone shape of the present invention can also be used to reduce the base drag of a projectile such as the casing 300 shown in FIGS. 15 and 16. This type of projectile rotates in flight about a longitudinal axis, such as the axis 302 of the shell 300 to be aerodynamically stable. The direction of rotation is broken out by arrow R. This casing 300 has an axial velocity V indicated by the vector V ₁ . The vector V ₂ is in contact with the shell surface 306 and represents the rotational speed of the coalescing outer surface 306 at the downstream string 304 of the shell. Each valley extends generally parallel to the synthesis direction of the vectors V ₁ and V ₂ . The direction of the bone is required for the fluid to flow into the bone in a direction generally parallel to the bone length.

Next, when the bi-fowler pulse is first applied to Xn and then two pulses are applied to the signal line Xn after the time T _l , Ym and Ym + l are in the non-voltage state and the voltage state, respectively, so that the pixel Zn where n1 is a non-voltage state and pixels Zn and m + l are voltage states, respectively. The field is applied to Xn + 1. At this time, since both Ym and Ym + 1 are in a voltage state, the pixels Zn + 1, m and the pixels Zn + 1, m + 1 are also shown in this embodiment, but the bone is shown in FIGS. It may have a shape as shown in the example (U-shaped wave-shaped and smoothly corrugated in cross section perpendicular to the downstream direction).

The invention can also be applied to the thin blade rear of an airfoil, such as the compressor rotor blades of the gas turbine engine shown in FIGS. 17-13. This airfoil is generally indicated by reference numeral 400. The direction of the engine shaft is indicated by arrow 401 in FIG. 19 which is the downstream direction. The airfoil 400 has a high pressure surface 402 and a low pressure surface 404 that converge toward one another to form a thin wing rear portion 406. The airfoil's thin wing rear is not considered to be normally blunt, but the fluid boundary layer attached to the high and low pressure surfaces and maintained until the end of the airfoil is a way to create a narrow and non-negligible separation zone just one day after the wing's immediate vicinity. It is thought to separate from wing rear part. Thus, for the purposes of this embodiment, it is believed that this end surface 407 should be a blunt end surface.

In this embodiment, the bone of the present invention is formed on both the low pressure surface 404 (gol 408) and the high pressure surface 404 (gol 410), but only one of these surfaces is also within the scope of the present invention. I think. If there are valleys on both the high and low pressure surfaces, the exit of the valley on one surface is preferably offset laterally from the valley on the other surface (asymmetrical bone formation). Should not exceed about 50%).

Each bone extends in a direction substantially parallel to the direction of fluid flow in the immediate vicinity of the lying surface of the ear bone. The purpose of this is to orient the bone so that fluid flow enters into each bone essentially parallel to the direction of bone length. Due to the rotation of the vane, the local fluid flow direction adjacent the vane surface changes along the vane length. Thus, the direction of the bone will change along the wing length as does the radial component of the fluid velocity. This direction will be selected based on flight conditions for maximum benefit.

In this embodiment both sides of the high pressure surface and the low pressure surface extend to the surface 407 between the edges 412 of the adjacent valleys. As described with respect to another embodiment of the present invention, the lateral distance between adjacent bone outlets of each surface is such that the area projected downstream of the blunt end surface 407 laterally lying between the exit edges of adjacent bones of each surface is at least one outlet of the bone. It should be chosen to be about one quarter of the area.

As shown in the other airfoil embodiments of FIG. 20, the valley 500 also creates an airfoil high pressure surface 502 and a low pressure surface 504 in the wing region 506, or a high pressure surface 502 or low pressure surface 504. Can be formed. This embodiment is projected downstream of the blunt wing back 508 so as to be larger than the area of the longitudinal cross section 510 taken upstream of the wing posterior surface along the valley inlet as shown by the dotted line 512. Virtually increases the surface area. Pure bass dag decreases despite the increase in blunt area.

While the invention has been shown and described with reference to embodiments, it will be understood by those skilled in the art that various other changes and omissions in form and detail of the invention can be made without departing from the spirit and scope of the invention.

Claims (40)

In an object lying in a fluid flowing downstream with respect to an object, the object generally has a first surface extending downstream, the blunt end surface immediately downstream of the first surface meets the first surface and is generally downstream And the plurality of adjacent valleys formed on the first surface extend in an axial direction, the direction of which is a streamline of fluid flow adjacent to the surface on which the valleys are placed, the valleys being continuous up to the end surface. Make a plurality of adjacent bone outlets on the end surface, each bone having a pair of downstream sidewall surfaces that intersect the end surface and create a lateral edge of the bone outlet, wherein the blocky end surface area is Extending laterally from each lateral edge of the bone exit of the lateral edge of the adjacent bone exit over the entire length of the respective lateral edge, The bone has an inlet and gradually increases from the depth of the inlet to the maximum depth, the size and shape of the bone and the size of the first zone immediately following the blunt end surface of each bone over its full length. An object that is designed to flow completely into space, reducing base drag. The object of claim 1, wherein the zone projected downstream of the blunt end surface laterally situated between the pair of adjacent bone outlets is at least one quarter of the zone projected downstream of the adjacent bone outlet. The method of claim 1, wherein the pair of sidewall surfaces of each valley are substantially parallel to the direction of fluid flowing across the first surface in the vicinity of the valley over a generally continuous portion of the bone length and the continuous portion is An object having a bone outlet. 4. The object of claim 3, wherein each of the valleys is smoothly U-shaped along its length in a cross section perpendicular to the downstream direction. 5. The object of claim 4, wherein the plurality of valleys create a smooth corrugated surface that is wavy in cross section perpendicular to the downstream direction. 3. The object of claim 2, wherein the lines abutting each sidewall of the pair of bone sidewalls at the steepest point of the bone exit in a cross section perpendicular to the downstream direction are generally parallel. The object of claim 1, wherein the total area projected downstream of the bone outlet is less than about 30% of the area projected downstream of the blunt end surface. The device of claim 1, wherein the object generally has a second surface extending downstream, the surface being away from the first surface and generally facing in the opposite direction, the blunt end surface being immediately downstream downstream of the second surface. Is located and meets the second surface and a plurality of the valleys are formed on the second surface, and the blocky end surface area extends from each side edge of the valley on the second surface to the entire length of each side edge. An object characterized by extending laterally to the side edges of adjacent bones. 9. The zone of claim 8 wherein the projected region downstream of a blunt end surface disposed laterally between a pair of adjacent bone outlets on each surface of the first and second surfaces is downstream of one outlet of the pair of bone outlets. At least one quarter of the projected area. 9. The object of claim 8, wherein said pair of side surfaces of each bone are generally parallel to the direction of fluid flow on the surface where said bone is disposed over a generally continuous portion of said bone length. 11. The object of claim 10, wherein each of the valleys is smoothly U-shaped along its length in a cross section perpendicular to the downstream direction. 11. The object of claim 10, wherein the total area projected downstream of the bone outlet is less than about 30% of the area projected downstream of the blunt end surface. 12. The object of claim 11, wherein at each of the surfaces of the first and second surfaces each of the plurality of valleys creates a smooth corrugated surface that is corrugated in a cross section perpendicular to the downstream direction. 13. The object of claim 12, wherein the lines abutting each sidewall of the pair of bone sidewalls at the steepest point of the bone outlet in a cross section perpendicular to the downstream direction are generally parallel. 13. The object of claim 12, wherein the blunt end surface has a generally flat surface perpendicular to the downstream direction. 13. The object of claim 12, wherein the object is a vehicle and the blunt end surface is a rear end surface of the vehicle. A vehicle lying in fluid flowing downstream with respect to a vehicle, the vehicle having a blunt rear end surface and a first surface having a first plurality of adjacent downstream valleys, each of the valleys ending at the rear end surface. A plurality of bones are formed away from the bone exit of the end surface, and each of the valleys has a pair of sidewall surfaces extending in a day intersecting the posterior end surface to form a lateral edge of the bone exit, and the rear end surface The first portion of extends laterally from each said lateral edge to the lateral edge of an adjacent bone outlet over the entire length of each lateral edge, each of said valleys having an inlet and gradually increasing from the depth 0 to the highest depth of said inlet. Increasing the shape and size of the bone and the size of the first portion so that each bone flows completely through its length and is downstream of the posterior end surface. Flowing a fluid into the space behind in the vehicle, characterized in that to reduce the base drag. 18. The system of claim 17, wherein the downstream projected area of the posterior end surface disposed laterally between the pair of adjacent end exits of the first multiplicity of bones is at least one of the projected downstream of one exit of the pair of adjacent bone exits. A vehicle characterized by being / 4. 18. The method of claim 17, wherein the pair of sidewall surfaces of each of the first plurality of bones is generally parallel to the direction of fluid flowing over the first surface in the vicinity of the bone over a generally continuous portion of the valley ring. And said continuous portion has said valley exit. 18. The vehicle according to claim 17, wherein each of the first plurality of bones is smoothly U-shaped along its length in a cross section perpendicular to the downstream direction. 21. The vehicle of claim 20, wherein the first plurality of valleys create a smooth corrugated surface that is corrugated in cross section perpendicular to the downstream direction. 19. The vehicle according to claim 18, wherein the lines abutting the sidewalls of the pair of bone angles at the steepest point of the valley exit in a cross section perpendicular to the downstream direction are generally parallel. 18. The vehicle according to claim 17, wherein the total area projected downstream of all the bone exits is about 30% smaller than the area projected downstream of the rear end surface. 18. The vehicle according to claim 17, wherein the vehicle has a second surface away from the first surface and making a second majority of bone extending generally downstream in the opposite direction and extending downstream. 25. The one or more bone outlets of the pair of bone outlets as recited in claim 24, wherein the zone projected downstream of the posterior end surface disposed laterally between the pair of adjacent bone outlets of the first majority and second majority bones At least one quarter of the area projected downstream of the vehicle. 25. The vehicle according to claim 24, wherein each of the first majority bone and the second majority bone is smoothly U-shaped along the bone length in a cross section perpendicular to the downstream direction. 25. The vehicle of claim 24, wherein the total projected area of all of the goal exits is less than about 30% of the projected area downstream of the rear end surface. 26. The vehicle of claim 25, wherein each of the first and second majority bones creates a smooth corrugated surface that is corrugated in a cross section perpendicular to the downstream direction. 27. The vehicle according to claim 25, wherein the lines abutting each sidewall of the pair of bone sidewalls at the steepest point of the valley exit in a cross section perpendicular to the downstream direction are generally parallel. 19. The vehicle according to claim 18, wherein the rear end surface is a surface that is perpendicular to the downstream direction and is generally flat. 25. The vehicle of claim 24, wherein the pair of sidewall surfaces of each valley is generally parallel to the direction of fluid flowing over the surface on which the valley is disposed over a generally continuous portion of the valley length. 18. The vehicle of claim 17, wherein each valley makes one large vortex from each sidewall surface, each vortex having an axis extending downstream, and the pair of vortices from each bone rotate in opposite directions. 2. The vehicle of claim 1, wherein each valley creates one large axial vortex from each of the sidewall surfaces and the pair of vortices from each valley rotate in opposite directions. A compressor airfoil of a gas turbine engine having a high pressure surface and a low pressure surface extending to a thin blade rear surface directed downstream, the compressor airfoil having a first plurality of adjacent and downstream valleys on at least one of the high pressure surface and the low pressure surface, Each of the bones terminates at the posterior surface of the wing to form a plurality of bones away from the posterior posterior surface bone outlet, and each of the bones has a pair of sidewall surfaces extending downstream to intersect the wing posterior surface. Forming a lateral edge of, wherein the first portion of the wing posterior surface extends laterally to the lateral edge of the adjacent bone exit from each lateral lateral edge over the entire length of each lateral edge, Having an inlet and gradually increasing from the depth 0 to the maximum depth of the inlet, at which outlet the bone depth is less than 50% of the wing posterior surface thickness The shape and size of the air bone and the size of the first portion make each bone complete the flow throughout its length, allowing fluid to enter the space immediately downstream downstream of the posterior posterior surface of the wing to reduce base drag. Compressor airfoil of the gas turbine engine, characterized in that the loss. The area projected downstream of the wing posterior surface disposed laterally between a pair of adjacent bone exits of the first plurality of bones is at least 1 / th of the area projected downstream of the pair of adjacent bone exits. Compressor airfoil of the gas turbine engine, characterized in that 4. 35. The method of claim 34, wherein the pair of sidewall surfaces of each of the first plurality of bones is generally in the direction of fluid flowing on the surface where the bone is disposed near the bone over a generally continuous portion of the bone length. A parallel, said continuous portion having said bone outlet. 35. A compressor airfoil of a gas turbine engine according to claim 34, wherein each of the first plurality of bones is gently U-shaped along its length in a cross section perpendicular to the downstream direction. 38. The compressor airfoil of a gas turbine engine according to claim 37, wherein the first plurality of bones create a smooth corrugated surface in a cross section perpendicular to the downstream direction. 35. The compressor airfoil of a gas turbine engine according to claim 34, wherein the lines abutting the angular walls of the pair of bone side walls at the steepest point of the bone outlet in a cross section perpendicular to the downstream direction are substantially parallel. 35. The compressor airfoil of claim 34, wherein the high pressure surface and the low pressure surface have a plurality of downstream valleys.

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