CN1318830C

CN1318830C - Submarine sediment transport simulation method

Info

Publication number: CN1318830C
Application number: CNB2005100661274A
Authority: CN
Inventors: 林缅; 袁志达
Original assignee: Institute of Mechanics of CAS
Current assignee: Institute of Mechanics of CAS
Priority date: 2005-04-21
Filing date: 2005-04-21
Publication date: 2007-05-30
Anticipated expiration: 2025-04-21
Also published as: CN1664252A

Abstract

The present invention discloses a submarine sand transport simulation method. The present invention comprises the procedures: 1. a layer of sand with proper thickness is evenly laid at the bottom of a water tank provided with a wave-shaped seabed model; 2. water is injected in the water tank, and disturbance of water streams to a sand surface is reduced as much as possible in the process of water injection; 3. a water body is driven to oscillate to ensure that swirls formed by water streams can lift and drive sand to move; 4. a laser sheet light source is adopted, light beams irradiate the middle part of a sand layer on the surface of a seabed, and the image information of the process is collected through a video camera; 5. after sand on the surface of the seabed model is completely transported to parts near to both sides of the water tank through sufficient oscillation time, oscillation is stopped. The present invention provides theoretical bases for pipe installation and engineering construction on seabeds with various surface shapes through research to the transportation conditions of wave-shaped seabed sediments of shallow sea areas, and blindness on design can be avoided.

Description

A kind of submarine sediment transport simulation method

Technical field

The present invention relates to the analogy method of the wavy bottom sediment bypassing in a kind of shallow water marine site.

Background technology

Field observation shows that shallow water marine site bottom is the wavy husky body that exists various different scales, and they present with unsymmetric form mostly.Under hydrodynamisms such as trend, wave, these asymmetrical wavy husky bodies are unsettled, move with certain speed, and flow velocity, bottom shape and silt character or the like are determining sediment transport rate and the defeated direction of moving near the bottom.Bring a series of problems thus.Such as, the pipeline by the bed ripples district may expose, even by unsettled.The navigation channel can be stopped up owing near bed ripples moves.Consider from the angle of safety and economic interests, the optimization of pipeline safety and pipeline buried depth, the navigation channel operation all is that the investor is concerned about the most with desilting expense profit and loss or the like.Therefore the sediment bypassing of studying under the asymmetric wavy bottom seems particularly important.

Summary of the invention

Problem at prior art exists the object of the present invention is to provide a kind of submarine sediment transport simulation method.

For achieving the above object, a kind of submarine sediment transport simulation method provided by the invention comprises the steps:

1) grains of sand of drying in a process that is provided with the even layer overlay suitable thickness of bottom of gullet of wavy sea bed model;

2) water filling in tank reduces current as far as possible to the Shamian Island disturbance in the injecting process, to guarantee that the grains of sand evenly rest on the sea bed model surface;

3) drive the water body vibration, can start, drive grains of sand motion to guarantee the whirlpool that current form;

4) adopt laser light sheet, and with the middle part of light beam irradiates at sea bed surface sand bed, with flow condition that reflects the sea bed model surface grains of sand on a certain section and the moving situation of the grains of sand in water body of throwing, and the image information of this process of camera acquisition of passing through;

5) through sufficient duration of oscillation, treat on the sea bed model face the grains of sand fully by defeated move on near the tank both sides after, the failure of oscillations.

Further, also comprise the steps:

6) discharge water in the tank, collect near the grains of sand the tank both sides respectively fully;

7) grains of sand of collecting are fully dried, write down its quality respectively.

Further, to be shaped as wavy, the cosine of symmetry asymmetric wavy or index is asymmetric wavy for described wavy sea bed model surface.

Further, the bonding one deck grains of sand layer in described wavy sea bed surface, this layer grains of sand only its side surface and model ontology relative with the sea bed body are mutually bonding, and other surfaces of the grains of sand are all exposed outside with its natural form.

The present invention for pipe installation and engineering construction on various surface configuration sea beds provide theoretical foundation, avoids the blindness that designs by the defeated research that moves situation to the wavy bottom silt in shallow water marine site.

Description of drawings

Fig. 1 is an analogue means duty partial schematic sectional view of the present invention;

Fig. 2 be among Fig. 1 A to partial schematic diagram;

Fig. 3 is a B-B sectional view among Fig. 1;

Fig. 4 be among Fig. 1 C to partial schematic diagram;

Fig. 5 is another kind of sea bed model sectional schematic diagram;

Embodiment

The sink structure that is provided with wavy sea bed of the present invention as shown in Figures 1 to 4, U-shaped pipe 8 openings are provided with vertically upward, its right-hand member is open state, be communicated with atmosphere, suitably highly locating to be provided with a pressure transducer 9, U-shaped pipe 8 left ends join by a pipeline 2 and a blower fan 1, be provided with an operation valve 3 between pipeline 2 and the U-shaped pipe 8, section middle part, 8 end of U-shaped pipe is provided with sea bed model construction section 20, sea bed model 14 is installed in this construction section 20, sea bed model construction section 20 tops are provided with a laser light sheet 7, and a side of sea bed model construction section 20 is provided with a video camera 16 (see figure 3)s.

The housing 18 and the U-shaped pipe 8 of operation valve 3 are made into integration, its inner chamber is equipped with a valve plate 6 by rotating shaft 4, operation valve 3 housings one side external surface is provided with a stepping actuating motor 17 (see figure 4)s, the output shaft of this servomotor 17 links to each other with rotating shaft 4, the housing 18 of operation valve 3 is provided with two opening ports 5, the position of these two opening ports 5 is corresponding with two working positions of valve plate 6 respectively, that is: valve plate 6 is when shown position, top opening port 5 makes pipeline 2 be communicated with atmosphere, and right side opening port 5 makes U-shaped pipe 8 left ends be communicated with atmosphere; When being in its 2nd working position about valve plate 6 revolves and turn 90 degrees, two opening ports 5 are all sealed by valve plate 6, and pipeline 2 is connected with U-shaped pipe 8 left ends.

U-shaped pipe 8 is made by transparent material, its section is the rectangle (see figure 3), its end section diapire is provided with a draining

valve

21,8 end of U-shaped pipe sea bed model construction section 20 1 sides at section middle part are provided with a dismountable shrouding 10, video camera 16 is positioned at shrouding 10 1 sides, another relative with shrouding 10 in the sea bed model construction section 20 sidewall is provided with a light shield layer 13, be not equipped with a light shield layer 13 equally on sea bed model construction section 20 roofs, these light shield layer 13 middle parts have a strip optical transmission window 11 that is complementary with following irradiating light beam 12 shapes of laser light sheet 7.

During analogue means work, carry out according to following steps:

1) grains of sand 15 of drying in the process of the even layer overlay suitable thickness in the surface of wavy sea bed model 14;

2) in U-shaped pipe 8, put into an amount of water 19, reduce current in the injecting process as far as possible, to guarantee that the grains of sand evenly rest on sea bed model 14 surfaces to the Shamian Island disturbance;

3) pass through the hunting frequency that the control device (not shown) is set valve plate 6 in the operation valve 3, start blower fan 1 outside exhausting, along with valve plate 6 switches in the circulation of two working position, water in the U-shaped pipe 8 is reciprocating vibration in managing under the effect of blower fan 1 and atmosphere, the current that are positioned at sea bed model 14 places form the wave flow that back and forth flows thus the grains of sand 15 are washed away, and with the grains of sand 15 to the model both sides or a side is defeated moves;

4) adopt laser light sheet 7, and with the middle part of light beam irradiates at sea bed model 14 surperficial sand beds, with flow condition that reflects the sea bed model surface grains of sand on a certain section and the moving situation of the grains of sand in water body of throwing, and pass through the image information that video camera 16 is gathered these processes.Because the initial stage amplitude instability of the current starting oscillation in the U-shaped pipe 8, in order to absorb effective ocean current sediment transport form, must treat to carry out after the waterflow stabilization vibration, at this moment by pressure transducer 9 can whether stable oscillation stationary vibration detects to current, after treating the waterflow stabilization vibration, pressure transducer 9 sends to control device with detection signal, and control device control laser light sheet 7 and video camera 16 are started working.Adopt laser light sheet, and with the middle part of light beam irradiates at sea bed model 14 surperficial sand beds, simultaneously on U-shaped pipe 8 sidewalls on video camera opposite, light shield layer 13 is set, can guarantee that video camera 16 only absorbs defeated the move image of sand bed middle part under flow action, help to eliminate the influence of sand bed boudary portion, thereby obtain the image information more approaching with actual conditions;

5) through sufficient duration of oscillation, treat on 14 on the sea bed model the grains of sand fully by defeated move on near the tank both sides after, the failure of oscillations;

6) by draining valve 21 water in the U-shaped pipe 8 is discharged, collect respectively and be washed near the grains of sand in sea bed model 14 both sides;

In order to guarantee that the current in the U-shaped pipe 8 produce stable vibration, the switching frequency of valve plate 6 is preferably identical with the natural frequency of vibration of U-shaped pipe 8.

As shown in Figure 5, at the sediment transport situation of different shape sea bed under action of ocean current, can be studied by the sea bed model that replacing has a different surfaces shape.For the configuration of surface that makes sea bed model 14 more near actual conditions, model surface needs bonding one deck grains of sand layer, this layer grains of sand only its side surface and model ontology relative with model ontology are mutually bonding, and other surfaces of the grains of sand are all with the exposed (not shown) outside of its natural form.

Table 1 is the sea bed model sediment transport contrast table of different surfaces shape

The bottom shape	Husky gross weight (g)	Mild side husky heavy (g)	Steep side husky heavy (g)	Ratio is approximate
The bottom shape	Husky gross weight (g)	Mild side husky heavy (g)	Steep side husky heavy (g)	Ratio is approximate	Symmetry	160	68	72	0.94
Index is asymmetric	160	121	12	10.08	Symmetry	160	68	72	0.94
Index is asymmetric	160	121	12	10.08	Cosine is asymmetric	160	90	38	2.37

Claims

1, a kind of submarine sediment transport simulation method is characterized in that, comprises the steps:

2, a kind of submarine sediment transport simulation method according to claim 1 is characterized in that, also comprises the steps:

3, a kind of submarine sediment transport simulation method according to claim 1 and 2 is characterized in that, it is asymmetric wavy or index is asymmetric wavy that described wavy sea bed model surface is shaped as wavy, the cosine of symmetry.

4, a kind of submarine sediment transport simulation method according to claim 3, the bonding one deck grains of sand layer in described wavy sea bed surface, this layer grains of sand only its side surface and model ontology relative with the sea bed body are mutually bonding, and other surfaces of the grains of sand are all exposed outside with its natural form.