CN101936057A - Fujian Tulou Pneumatic Air Guide Device - Google Patents

Abstract

The invention discloses an aerodynamic wind guiding device for Fujian Tulou, which is a wind guiding ring plate erected at the roof ridge of Fujian Tulou. After adopting the above scheme, the present invention adopts structural aerodynamic technology to erect the wind guide ring plate around the roof ridge of Fujian Tulou, which can change the air flow state of the high-speed airflow around the roof overhang during typhoon, and effectively reduce the air force acting on the roof surface. Wind load, so as to prevent and reduce the wind-induced damage of the roof. Its working principle can be explained by Dayu's concept of water control: Dayu can effectively reduce flood disasters, and its water control plan is realized by "drainage" instead of "water blocking", so the device of the present invention is called " Wind guide" rather than "wind resistance". Adopting the air guide device of the present invention does not need to strengthen the rigidity and strength of the roof and its supporting components, does not affect the normal use state of the earth building, does not change the appearance of the earth building, and has good protection significance and application value.

Description

Fujian Tulou Pneumatic Air Guide Device

technical field

The invention relates to the protection of world heritage sites and the field of structural wind engineering, in particular to a pneumatic wind guiding device for Fujian Tulou.

Background technique

In 2008, "Fujian Tulou" was approved to be included in the "World Heritage List", which is very important for its protection. Fujian Tulou are distributed in the southeast coastal area, and it is not uncommon for them to be damaged by typhoons. Because the roof has a large eaves and is supported by a wooden frame underneath, it is sensitive to wind loads, and the roof is often damaged during typhoons.

In the prior art, there are many wind-resistant measures for buildings, but they generally meet the requirements by strengthening the strength and rigidity of the structure, which will affect the original and overall appearance of the Tulou World Heritage Site, which does not meet the protection needs of the heritage.

Contents of the invention

The purpose of the present invention is to provide a pneumatic wind guide device for Fujian Tulou, which can solve the problem of wind-induced damage to the roof of Fujian Tulou without changing the original appearance of the Tulou.

In order to achieve the above object, the present invention adopts the following technical solutions:

The aerodynamic wind guide device of Fujian Tulou is a wind guide ring plate erected on the roof ridge of Fujian Tulou.

The material of the above-mentioned wind guide ring plate is made of earthen bricks and tiles, which can be consistent with the original building materials of the earth building.

The ratio of the height of the wind guide ring plate to the height of the ridge of the Fujian Tulou is 0.01-0.05.

After adopting the above-mentioned scheme, the present invention adopts structural aerodynamic technology, and arranges a circular vertical air guide ring plate at the roof ridge of Fujian Tulou, which can change the air flow state of the high-speed airflow around the overhanging eaves of the roof during typhoons, and effectively reduce the impact on the roof surface. wind load, so as to prevent and reduce the wind-induced damage to the roof. Its working principle can be explained by Dayu's concept of water control: Dayu can effectively reduce flood disasters, and its water control plan is realized by "drainage" instead of "water blocking", so the device of the present invention is called " Wind guide" rather than "wind resistance". The air guide device of the present invention does not need to strengthen the rigidity and strength of the roof and its supporting components, does not affect the normal use of the earth building, does not change the appearance of the earth building, and has good protection significance and application value.

The air guide device of the present invention is simple in structure, only needs to increase the slight height of the ridge uplift, especially can be made of brick and tile materials (of course, other materials can also be used), maintains the original antique flavor of the earth building, and does not damage the original taste of the world heritage of the earth building The overall appearance meets the protection needs of the heritage.

The air guiding device of the present invention has wide adaptability, and is not only suitable for circular earth building buildings (including circular and square), but also has a good aerodynamic unloading effect for non-circular earth building buildings (such as semicircular and Π-shaped).

Description of drawings

FIG. 1 is a schematic structural view of Embodiment 1 of the present invention;

Fig. 2 is the zoning diagram of the earth building in Embodiment 1 of the present invention;

Figure 3 is a vertical sectional view of Embodiment 1 of the present invention;

Fig. 4 is a schematic diagram of the net wind pressure coefficient at the outer overhanging eaves of Embodiment 1 of the present invention;

Fig. 5 is a schematic diagram of the net wind pressure coefficient at the inner overhanging eaves of Embodiment 1 of the present invention;

FIG. 6 is a schematic structural diagram of Embodiment 2 of the present invention;

Fig. 7 is the partition diagram of the earth building in the second embodiment of the present invention;

Fig. 8 is a schematic diagram of the net wind pressure coefficient of the outer overhanging eaves in the second embodiment of the present invention at a wind direction angle of 0°;

Fig. 9 is a schematic diagram of the net wind pressure coefficient of the outer overhanging eaves of the second embodiment of the present invention at a wind direction angle of 30°;

Fig. 10 is a schematic diagram of the net wind pressure coefficient of the outer overhanging eaves in the second embodiment of the present invention at a wind direction angle of 45°;

Fig. 11 is a schematic diagram of the net wind pressure coefficient of the outer overhanging eaves in the second embodiment of the present invention at a wind direction angle of 60°;

Fig. 12 is a cross-sectional wind velocity vector diagram before the wind guide ring plate is installed in Embodiment 1 of the present invention;

Fig. 13 is a cross-sectional wind velocity vector diagram after the wind guide ring plate is installed in Embodiment 1 of the present invention;

Detailed ways

The implementation cases of the most typical circular and square circular earth buildings are now illustrated

Embodiment one:

Fujian Tulou aerodynamic air guide device of the present invention, embodiment 1 takes a circular earth building as an example, as shown in Figure 1, this pneumatic air guide device is a wind guide ring plate 1 erected around the ridge of the circular earth building 3. The division of circular earth buildings is shown in Figure 2, and Figure 3 is a vertical cross-sectional view of circular earth buildings. Assume that the height of the wind guide ring plate 1 is h, and the height of the ridge of the circular earth building 3 is H. In order to reflect the influence of the height h of the wind guide ring plate 1 on the wind pressure of the roof, the aerodynamic effect is analyzed according to the different values of h in Table 1. The modeling of the circular earth building is based on the actual size, and the height H of the ridge of the circular earth building is taken = 11m, take the distance between the inner and outer walls of a circular earth building as d, d = 5m, and the radius R = 0.55H.

Table 1

The numerical simulation method of Computational Fluid Dynamics is used to calculate the distribution law of the wind direction angle and the height of the ring plate on the roof wind load, so as to analyze the unloading effect of aerodynamic measures.

In aerodynamics, the wind pressure coefficient is a dimensionless number relative to a reference point, which can be expressed as:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&rho;</span>}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

是参考点的风速。In the formula: C _pi is the wind pressure coefficient of a certain measuring point i on the building surface; p _i is the net wind pressure of measuring point i;

is the wind speed at the reference point.

The average wind pressure coefficient of the roof in this paper is defined as C _p , which is obtained by weighting the wind pressure coefficient C _pi of each calculation point according to the area Ai to which the point belongs, and its calculation formula is

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; Pi</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}$

In actual engineering, the net wind pressure coefficient on the surface is generally used, also known as the net wind carrier type coefficient.

In this paper, by partitioning the upper and lower surfaces of the roof, the difference between the average wind pressure on the upper and lower surfaces can be used to represent the net wind pressure coefficient ΔCp of the roof, as follows:

ΔCp= _Cp'Up - _CpDown

In Table 1 and Table 2, h is the height of the air guide ring plate 1, H is the height of the ridge of the circular earth building, h/H=0 means that there is no air guide ring plate, and e is the load reduction of the average net wind pressure coefficient Rate:

$\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}<span\; class="notranslate">\; |</span>}{<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; \&Delta;C</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; |</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

Among them, ΔCp _0j : the net wind pressure coefficient of wind direction angle j when there is no wind guide ring plate (j represents the change of wind direction angle). ΔCp _ij corresponds to the net wind pressure coefficient of j wind direction angle i measuring point (i represents the change of measuring point).

As shown in Figures 4 and 5, the net wind pressure coefficient of the outer overhanging eaves of the circular earth building 3 is larger than that of the inner overhanging eaves, and the overall net wind pressure coefficient at the inner overhanging eaves is very small. The net wind pressure coefficient is the largest, which is the most unfavorable position. When the height of the wind guide ring plate is set to 0.05H, the net wind pressure coefficient in W1 area changes from -1.5 to -0.65, and the decompression can reach more than 50. The effect is obvious. The specific load reduction rate is shown in Table 2.

Table 2

Embodiment two:

Embodiment 2 Taking a square earth building as an example, as shown in Figure 6, the pneumatic air guiding device is a wind guiding ring plate 2 erected at the ridge of the square earth building 4, and the division of the square earth building is shown in Figure 7. The height of the ring plate 2 is h, and the height of the ridge of the square earth building 4 is H. In order to reflect the influence of the height h of the wind guide ring plate 2 on the wind pressure of the roof, it is also simulated and calculated according to the h value in Table 1. The modeling of the square earth building is based on the actual size. The height of the ridge of the square earth building is H = 11m, and The distance between the inner and outer walls of a square earth building is d, where d=5m, and the side length 2R=1.4H.

Using the numerical simulation method of Computational Fluid Dynamics for similar analysis, as shown in Figure 8-11, it can be seen that after the wind guide ring plate 2 is installed, the outer overhanging eaves have decompression effects in all wind direction angles , the most unfavorable position on the whole is the W1 area and W8 area under the wind direction angle of 0°. At this time, the net wind pressure coefficient is about -1.82. The load shedding rate is 45, and the specific decompression rate of unfavorable positions under each wind direction angle is shown in Table 3.

table 3

The wind guide ring plate installed in the tulou can reduce the wind load value of the roof, and its aerodynamic load reduction mechanism can be explained by the characteristics of the aerodynamic flow field. Figures 12-13 are the comparison diagrams of the wind field before and after the wind guide ring plate is installed on the roof ridge of a circular earth building. From the comparison of the wind field in Figure 12-13, it can be seen that the air guide ring plate installed reduces the impact of the airflow on the upper surface, thereby playing a role The effect of reducing wind loads. After the wind guide ring is installed, the separation of the incoming flow at the front edge of the roof overhang is gradually weakened, and an obvious backflow is formed on the leeward overhang, which collides with the windward incoming flow to offset the high negative pressure of the roof ridge, and the overall turbulence intensity of the roof is reduced; The intensity of the columnar vortex inside the circular earth building gradually weakens, the vortex on the leeward side becomes smaller, and the wake develops more fully.

Claims (3)

1. The aerodynamic air guide device for Fujian Tulou is characterized in that it is an air guide ring plate erected on the roof ridge of Fujian Tulou. 2. The aerodynamic air guide device for Fujian Tulou according to claim 1, characterized in that: the material of the above-mentioned air guide ring plate is made of earthen bricks and tiles, which can be consistent with the original building materials of the Tulou. 3. The aerodynamic air guide device for Fujian Tulou according to claim 1, characterized in that the ratio of the height of the air guide ring plate to the height of the Fujian Tulou roof ridge is 0.01-0.05.

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