Evaluation method for improving wind resistance reserve of roof structure by using flow control device

Abstract

The invention provides an evaluation method for improving wind resistance reserve of a roof structure by applying a flow control device, and belongs to the technical field of roof wind resistance. The method comprises the steps that S1, a wind load standard value formula used for enclosure structure design is determined according to a roof structure wind load standard; s2, determining a corresponding relation between the basic wind pressure and a wind load standard value; s3, according to the corresponding relation between the basic wind pressure and the incoming flow wind speed, determining an incoming flow wind speed formula corresponding to the area where the to-be-evaluated building model is located; s4, marking the ratio of the incoming flow wind speed increase value before and after the flow control to the incoming flow wind speed before the flow control is applied as a wind resistance capacity reserve factor expression; and S5, calculating a wind resistance reserve factor of the to-be-evaluated building model roof structure after the flow control mode is applied. The larger the value of the wind-resistant capacity reserve factor is, the better the flow control effect of the roof structure of the building model to be evaluated is, and the larger the wind-resistant capacity of the roof structure is.

Description

Technical Field

[0001] This invention relates to an assessment method for enhancing the wind resistance reserve of roof structures using a flow control device, belonging to the field of roof wind resistance technology. Background Technology

[0002] With the rapid development of infrastructure construction and the widespread application of new high-strength lightweight materials, low-rise, large-span buildings are increasingly becoming lighter. The roof structures of low-rise, large-span buildings are typical wind-sensitive structures, and wind load is one of the important factors affecting their structural safety. In recent years, the safety and stability of roof structures under strong wind loads have become increasingly prominent issues. Especially under extreme weather conditions such as typhoons, wind-induced vibration and wind-induced damage to roof structures can lead to serious economic losses and casualties. Therefore, improving the wind resistance of lightweight steel roof structures and reducing the wind hazards of roof structures has become an important research direction in the field of wind engineering.

[0003] Currently, there are two main types of measures commonly used to improve the wind resistance of roof structures: structural measures and flow control measures. Structural measures improve the overall stiffness and mass of the structure by using efficient materials or structural systems, and increasing the cross-section of components. Flow control measures improve the airflow characteristics of the building structure by altering the structural shape, using additional aerodynamic devices, or actively interfering with the local flow field using external energy, thereby reducing the impact of wind loads on the structure and improving its wind resistance. Among these, using additional aerodynamic devices to change the roof flow field and reduce the wind-induced effects on the structure, thus reducing roof wind pressure and improving the structure's wind resistance, is a relatively proactive wind-resistant measure that avoids limitations imposed by building form and function. This method is simple in structure, has a clear control mechanism, lower economic cost, higher efficiency, and wider applicability. How to quantitatively evaluate the effect of flow control methods on improving the wind resistance of structures is a very important issue. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and to provide an evaluation method for improving the wind resistance reserve of roof structures by applying a flow control device.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] An assessment method for enhancing the wind resistance reserve of a roof structure using a flow control device includes the following steps:

[0007] Step S1: Determine the standard wind load value for the building envelope design based on the roof structure wind load standard. The calculation formula;

[0008] Step S2: Based on the standard value of wind load in step S1 The calculation formula is used to determine the basic wind pressure. Standard value of wind load The correspondence;

[0009] Step S3: Determine the building model to be evaluated, based on the basic wind pressure of the area where the building model is located. Corresponding incoming wind speed The corresponding relationship, and the basic wind pressure in step S2. Standard value of wind load The correspondence is used to determine the incoming wind speed in the area where the building model to be evaluated is located. The calculation formula;

[0010] Step S4: Apply flow control to the area where the building model to be evaluated is located using a flow control device. Record the increase in incoming wind speed before and after applying flow control as the ratio of the incoming wind speed before applying flow control to the wind resistance reserve factor. The expression is used, based on the incoming wind speed corresponding to the area where the building model to be evaluated is located in step S3. Calculation formula to determine wind resistance reserve factor The correspondence between the maximum and minimum external wind pressure coefficient and the internal pressure coefficient before and after the application of flow control;

[0011] Step S5: Substitute the maximum and minimum external wind pressure coefficients and internal pressure coefficients before and after applying flow control into the wind resistance reserve factor expression obtained in Step S4 to obtain the wind resistance reserve factor of the roof structure of the building model to be evaluated after applying flow control. Wind resistance reserve factor This reflects the proportion of the increase in incoming wind speed that the roof structure of the building model under evaluation can withstand relative to the incoming wind speed under the load standard. The larger the value, the better the flow control effect of the roof structure of the building model being evaluated, and the greater the improvement in the wind resistance of the roof structure.

[0012] Preferably, the standard value of wind load in step S1 The calculation formula is as follows:

[0013] ,

[0014] in: This represents the maximum value of the external wind pressure coefficient; This is the internal pressure coefficient; This is the wind pressure height coefficient at the average height of the roof. This is the basic wind pressure.

[0015] Preferably, the basic wind pressure in step S2 Standard value of wind load The correspondence is as follows:

[0016] .

[0017] Preferably, the basic wind pressure of the area where the building model to be evaluated is located in step S3. Corresponding incoming wind speed The correspondence is as follows:

[0018] ,

[0019] in: The basic wind pressure of the area where the building model to be evaluated is located; air density; The incoming wind speed corresponds to the area where the building model to be evaluated is located.

[0020] Preferably, the incoming wind speed corresponding to the area where the building model to be evaluated is located in step S3. The calculation formula is as follows:

[0021] .

[0022] Preferably, the flow control device in step S4 is a vortex generator, a guide vane, a spoiler, an air intake device, or an air blowing device.

[0023] Preferably, the wind resistance reserve factor in step S4 Expression and wind resistance reserve factor The correspondence between the maximum and minimum external wind pressure coefficient and the internal pressure coefficient before and after the application of flow control is as follows:

[0024]

[0025] in, The incoming air velocity of the structure before applying flow control; The incoming air velocity of the structure after flow control is applied; The maximum value of the external wind pressure coefficient before applying flow control; This represents the maximum value of the external wind pressure coefficient after applying flow control.

[0026] Preferably, the maximum and minimum external wind pressure coefficients and internal pressure coefficients before and after applying flow control in step S5 are obtained through actual measurement, wind tunnel testing, or numerical simulation.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention defines a wind resistance reserve factor. Through methods such as field measurement, wind tunnel testing, and numerical simulation, the wind pressure coefficient of the roof before and after applying flow control under different wind direction angles can be obtained. The wind resistance reserve factor is then calculated from the wind pressure coefficient of the roof before and after applying flow control. The wind resistance reserve factor reflects the proportion of the increase in the incoming wind speed that the roof structure of the building model to be evaluated can withstand relative to the incoming wind speed under the load standard. The larger the value of the wind resistance reserve factor, the better the effect of flow control on the roof structure of the building model to be evaluated, and the greater the improvement in the wind resistance of the roof structure.

[0029] This invention proposes an evaluation method for improving the wind resistance reserve of roof structures by applying a flow control device and verifies the effectiveness of the wind resistance reserve factor. It can intuitively evaluate the improvement effect of the roof's wind resistance reserve, thus providing a quantitative and reliable calculation basis for evaluating the improvement effect of wind resistance. Attached Figure Description

[0030] Figure 1 The flowchart illustrates the evaluation method for enhancing the wind resistance reserve of roof structures using a flow control device, as described in this invention.

[0031] Figure 2 This is a schematic diagram of the building model used in this invention.

[0032] Figure 3 This is a schematic diagram of the building model after the control method is applied in this invention.

[0033] Figure 4 This is a schematic diagram of the roof wind pressure before and after applying flow control measures to the roof in this invention; wherein:

[0034] Figure 4 (a) Schematic diagram of roof wind pressure before applying flow control measures to the roof;

[0035] Figure 4 (b) Schematic diagram of roof wind pressure after applying flow control measures to the roof.

[0036] Figure 5 This is a schematic diagram of the arrangement of monitoring points in this invention.

[0037] Figure 6 This is a schematic diagram of the fluid domain and mesh generation in the numerical model of this invention; wherein:

[0038] Figure 6 (a) is a schematic diagram of the fluid domain in the numerical model of this invention;

[0039] Figure 6 (b) is a top view of the grid division in this invention;

[0040] Figure 6 (c) is the front view of the mesh division in this invention.

[0041] Figure 7 This is a distribution map showing the calculated wind resistance reserve factor at monitoring points after applying flow control at different wind angles in this invention; wherein:

[0042] Figure 7 (a) Distribution of wind resistance reserve factor calculation results at monitoring points after applying flow control at a wind direction angle of 0°;

[0043] Figure 7 (b) Distribution of wind resistance reserve factor calculation results at monitoring points after applying flow control at a wind direction angle of 30°;

[0044] Figure 7 (c) Distribution of wind resistance reserve factor calculation results at monitoring points after applying flow control at a wind direction angle of 45°;

[0045] Figure 7 (d) is a distribution map of the calculated wind resistance reserve factor at the monitoring point after applying flow control at a wind direction angle of 60°;

[0046] Figure 7 (e) is a distribution map of the wind resistance reserve factor calculation results at the monitoring point after applying flow control at a wind direction angle of 90°. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented based on the technical solution of the present invention and provides detailed implementation methods, but the protection scope of the present invention is not limited to the following embodiments.

[0048] like Figure 1 As shown in this embodiment, the evaluation method for improving the wind resistance reserve of a roof structure using a flow control device, used to evaluate the improvement in the wind resistance of the roof structure, includes the following steps:

[0049] Step S1: According to the "Standard for Wind Load on Roof Structures", the standard value of wind load used for the design of the building envelope is determined. It should be calculated using the following formula:

[0050] ,

[0051] in: This represents the maximum value of the external wind pressure coefficient; This is the internal pressure coefficient (when the external surface wind pressure is positive, the internal pressure coefficient is -0.3; when the external surface wind pressure is negative, the internal pressure coefficient is +0.2). This is the wind pressure height coefficient at the average height of the roof. This is the basic wind pressure;

[0052] Step S2, based on the standard value of wind load in step S1 The calculation formula is used to determine the basic wind pressure. Standard value of wind load The correspondence is shown in the following formula:

[0053] ;

[0054] Step S3: Determine the building model to be evaluated, based on the basic wind pressure of the area where the building model is located. Corresponding incoming wind speed The corresponding relationship, and the basic wind pressure in step S2. Standard value of wind load The correspondence is used to determine the incoming wind speed in the area where the building model to be evaluated is located. The calculation formula is as follows:

[0055] ,

[0056] in: The basic wind pressure of the area where the building model to be evaluated is located; air density; The incoming wind speed corresponds to the area where the building model to be evaluated is located.

[0057] The incoming wind speed corresponding to the area where the building model to be evaluated is located. The calculation formula is as follows:

[0058] .

[0059] Step S4: Apply flow control to the area where the building model to be evaluated is located using a flow control device. Record the increase in incoming wind speed before and after applying flow control as the ratio of the incoming wind speed before applying flow control to the wind resistance reserve factor. The expression is used, based on the incoming wind speed corresponding to the area where the building model to be evaluated is located in step S3. Calculation formula to determine wind resistance reserve factor The correspondence between the maximum and minimum external wind pressure coefficient and the internal pressure coefficient before and after the application of flow control; wind resistance reserve factor. The mathematical expression is as follows:

[0060]

[0061] in, The incoming air velocity of the structure before applying flow control; The incoming air velocity of the structure after flow control is applied; The maximum value of the external wind pressure coefficient before applying flow control; This represents the maximum value of the external wind pressure coefficient after applying flow control.

[0062] Specifically, step S4 includes the following steps:

[0063] Step S41: In this embodiment, the flow control device can be a vortex generator, guide vane, spoiler, air intake device, or air blowing device, etc.; taking the use of a vortex generator for flow control as an example, the specific parameters of the building model and control measures are determined, as shown in the diagram. Figure 3 As shown, where, The length of the vortex generator. The height of the vortex generator. The angle for vortex generator arrangement. The installation spacing of the vortex generator is 90° between the two blades; for example... Figure 2 As shown, the building model has a length L=13.7m, a width B=9.1m, and a height H=4m.

[0064] Step S42: Based on the pre-selected parameters of the building model, establish the initial building model and the model after applying the control method, and select parameters such as wind direction angle, wind speed, and roughness for numerical simulation calculation; such as... Figure 4 The diagram shown illustrates the wind pressure on the roof before and after applying flow control measures. This represents the maximum value of the external wind pressure coefficient. This represents the maximum value of the external wind pressure coefficient after applying flow control.

[0065] Step S43: Determine the specific operating conditions, including wind direction angle, wind speed at a height of 10m, and ground roughness. For example, the wind direction angle is set to 0°, 30°, 45°, 60°, and 90°, the wind speed at a height of 10m is selected as 25m / s, and the ground roughness is selected as 0.15.

[0066] Step S44: Determine the location and number of wind pressure monitoring points. Set up monitoring points at suitable locations on the top surface of the model to extract the calculated wind pressure data. The monitoring points are set as follows: Figure 5As shown, on the top surface of the model with dimensions of 13792mm × 9220mm, the center of the first row of wind pressure monitoring points is 110mm from the edge of the top surface. The distance between the centers of adjacent monitoring points in the first row to the seventh row is 500mm. The distance between the centers of adjacent monitoring points in the seventh row and the eleventh row is 750mm. The distance between the centers of adjacent monitoring points in the eleventh row and the seventeenth row is 500mm. The distance between the center of the first column of wind pressure monitoring points and the left edge of the top surface is 196mm. The distance between the centers of adjacent monitoring points in the first column and the eighth column is 500mm. The distance between the centers of adjacent monitoring points in the eighth column and the sixteenth column is 800mm. The distance between the centers of adjacent monitoring points in the sixteenth column and the twenty-third column is 500mm.

[0067] Step S45: Establish a model based on the selected parameters, choose an appropriate computational domain size, and mesh the simulation model, such as... Figure 6 As shown;

[0068] Step S46: Set the solution conditions, including: the model used for calculation, the solution method, and the time step;

[0069] Step S47: Obtain the roof wind pressure of the metal roof simulation model under different wind direction angles through numerical simulation, thereby obtaining the roof wind pressure coefficient at each monitoring point of the roof under different wind direction angles. The wind pressure coefficient conversion formula is:

[0070] ,

[0071] in, The wind pressure coefficient at the measuring point; Pressure at points on the building surface; Static pressure at a reference height; The density of the incoming airflow; The average wind speed over buildings;

[0072] Step S48: Assuming the load-bearing capacity of the building model's top surface remains constant, determine the wind pressure that the building model's top surface can withstand after applying flow control. for:

[0073]

[0074] In the formula: The maximum value of the external wind pressure coefficient after applying flow control; Internal pressure coefficient.

[0075] Step S49, corresponding incoming air velocity for:

[0076] ;

[0077] Step S5: Substitute the maximum and minimum wind pressure coefficients before and after applying flow control into the expression for the wind resistance reserve factor to obtain the wind resistance reserve factor of the roof after implementing flow control. The wind resistance reserve factor value is 37.21% at a wind direction angle of 0°; 31.48% at a wind direction angle of 30°; 16.57% at a wind direction angle of 45°; 53.24% at a wind direction angle of 60°; and 41.5% at a wind direction angle of 90°. Figure 7 The figure shown is a distribution diagram of the wind resistance reserve factor calculation results at monitoring points after applying flow control under different wind direction angles in this invention.

[0078] The wind resistance reserve factor reflects the proportion of the increase in incoming wind speed that a building's roof structure can withstand relative to the incoming wind speed under load standard. The larger the value, the better the flow control effect and the greater the improvement in the structure's wind resistance.

[0079] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for evaluating the wind resistance reserve of a roof structure using a flow control device, characterized in that, Includes the following steps: Step S1: Determine the standard wind load value for the building envelope design based on the roof structure wind load standard. The calculation formula; Step S2: Based on the standard value of wind load in step S1 The calculation formula is used to determine the basic wind pressure. Standard value of wind load The correspondence; Step S3: Determine the building model to be evaluated, based on the basic wind pressure of the area where the building model is located. Corresponding incoming wind speed The corresponding relationship, and the basic wind pressure in step S2. Standard value of wind load The correspondence is used to determine the incoming wind speed in the area where the building model to be evaluated is located. The calculation formula; Step S4: Apply flow control to the area where the building model to be evaluated is located using a flow control device. Record the increase in incoming wind speed before and after applying flow control as the ratio of the incoming wind speed before applying flow control to the value of the increase in incoming wind speed before applying flow control as the wind resistance reserve factor. The expression is used, based on the incoming wind speed corresponding to the area where the building model to be evaluated is located in step S3. Calculation formula to determine wind resistance reserve factor The correspondence between the maximum and minimum external wind pressure coefficient and the internal pressure coefficient before and after the application of flow control; Step S5: Substitute the maximum and minimum external wind pressure coefficients and internal pressure coefficients before and after applying flow control into the wind resistance reserve factor expression obtained in Step S4 to obtain the wind resistance reserve factor of the roof structure of the building model to be evaluated after applying flow control. Wind resistance reserve factor This reflects the proportion of the increase in incoming wind speed that the roof structure of the building model under evaluation can withstand relative to the incoming wind speed under the load standard. The larger the value, the better the flow control effect of the roof structure of the building model being evaluated, and the greater the improvement in the wind resistance of the roof structure.

2. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 1, characterized in that, The standard value of wind load mentioned in step S1 The calculation formula is as follows: ， in: This represents the maximum value of the external wind pressure coefficient; This is the internal pressure coefficient; This is the wind pressure height coefficient at the average height of the roof. This is the basic wind pressure.

3. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 2, characterized in that, Basic wind pressure in step S2 Standard value of wind load The correspondence is as follows: 。 4. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 3, characterized in that, The basic wind pressure of the area where the building model to be evaluated is located in step S3. Corresponding incoming wind speed The correspondence is as follows: ， in: The basic wind pressure of the area where the building model to be evaluated is located; air density; The incoming wind speed corresponds to the area where the building model to be evaluated is located.

5. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 4, characterized in that, In step S3, the incoming wind speed corresponding to the area where the building model to be evaluated is located. The calculation formula is as follows: 。 6. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 1, characterized in that, In step S4, the flow control device is a vortex generator, a guide vane, a spoiler, an air intake device, or an air blowing device.

7. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 5, characterized in that, Wind resistance reserve factor in step S4 Expression and wind resistance reserve factor The correspondence between the maximum and minimum external wind pressure coefficient and the internal pressure coefficient before and after the application of flow control is as follows: in, The incoming air velocity of the structure before applying flow control; The incoming air velocity of the structure after flow control is applied; The maximum value of the external wind pressure coefficient before applying flow control; This represents the maximum value of the external wind pressure coefficient after applying flow control.

8. The evaluation method for enhancing the wind resistance reserve of a roof structure using a flow control device according to claim 1, characterized in that, The maximum and minimum values ​​of the external wind pressure coefficient and the internal pressure coefficient before and after applying flow control in step S5 are obtained by actual measurement, wind tunnel test or numerical simulation.

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