Numerical simulation method, apparatus and storage medium for wind and rain coupled erosion of building roofs

Abstract

This invention relates to a numerical simulation method, apparatus, and storage medium for wind-rain coupled erosion of building roofs. The method establishes a geometric model of the roof, extracts the computational domain model of the external flow field, and meshes it; it uses a k-e turbulence model to simulate the wind field, and when the wind field calculation converges, extracts the wind speed contour map of the flow field center profile, the roof wind speed vector map, and the roof dynamic pressure contour map; it uses an Eulerian-Lagrange model to simulate the wind-rain coupled field, and when the wind-rain coupled field calculation converges, extracts the DPM particle trajectory map; it uses an erosion / deposition model to calculate the roof erosion amount, and when the calculation converges, extracts the roof DPM erosion rate contour map, the roof surface friction coefficient contour map, and the roof z-direction erosion rate scatter plot; by comparing the various graphs and corresponding data, high-risk areas of wind-rain coupled erosion of the building roof are obtained. Compared with existing technologies, this invention has the advantages of quickly and efficiently identifying roof areas prone to leakage after rainwater erosion, and intuitively and accurately indicating roof areas requiring reinforcement design.

Description

Technical Field

[0001] This invention relates to the fields of building water supply and drainage and numerical simulation analysis technology, and in particular to a numerical simulation method, device and storage medium for wind and rain coupled erosion of building roofs. Background Technology

[0002] Rainfall is a common natural phenomenon, and its study is crucial in the construction industry. However, wind-driven rain is not a frequently used meteorological parameter. Wind-driven rain refers to rainwater falling under the influence of wind. In the absence of wind, rain falls vertically and tends to be evenly distributed on roofs. However, under the influence of wind, the trajectory of raindrops deviates, and raindrops become sparse in areas where the wind field is dispersed. Under the influence of wind, raindrops fall unevenly on the roof, creating erosion zones. Wind-driven rain is a significant factor affecting building safety and durability, and is a major source of roof erosion. It is particularly evident in the rain-rich southern regions and coastal areas with frequent strong winds and rain. Wind-driven rain can cause severe erosion of roofs, damage to the roof waterproofing layer leading to leaks, moisture accumulation in roof corners, and even serious structural damage from rainwater erosion.

[0003] Long-term rainfall monitoring, especially wind-driven rain measurement of buildings, is inconvenient, time-consuming, and labor-intensive, and only provides limited data. Currently, Computational Fluid Dynamics (CFD) simulation technology is increasingly being applied to rainwater simulation and related auxiliary design. For example, Chinese patent CN115146359A discloses a method for calculating the drainage performance of large-span roofs considering wind-rain coupling. This method utilizes a BIM information model platform, a CFD wind-rain multiphase flow coupling algorithm, and parameterized analysis of rainwater dynamic runoff to establish a collaborative and interconnected digital solution for dynamic analysis of large-span building roof drainage. Therefore, improving the convenience, saving time and labor costs in studying wind-rain coupling erosion of building roofs, and enabling more accurate and targeted building protection, has become a problem that needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology, such as the inconvenience, time and labor consumption of long-term rainfall monitoring, and the limited availability of single working conditions, and to provide a numerical simulation method, device and storage medium for wind and rain coupled erosion of building roofs.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] According to a first aspect of the present invention, a numerical simulation method for wind and rain coupled erosion of building roofs is provided, comprising the following steps:

[0007] S1, Obtain the geometric information of the building roof and establish the roof geometric model;

[0008] S2, Extract the external flow field computational domain model of the roof geometry model;

[0009] S3, perform mesh generation on the external flow field computational domain model;

[0010] S4. Use the Ke turbulence model to simulate the wind field, set the simulation parameters for the continuous phase, and when the wind field calculation converges, extract the wind speed cloud map of the flow field center profile, the wind speed vector map of the roof, and the dynamic pressure cloud map of the roof.

[0011] S5. Use the Euler-Lagrange model to simulate the wind and rain coupling field, set the simulation parameters of the discrete phase, and extract the DPM particle trajectory map when the wind and rain coupling field calculation converges.

[0012] S6. Calculate the roof erosion amount using the erosion / accumulation model in the discrete phase and interact with the continuous phase. When the calculation converges, extract the roof DPM erosion rate cloud map, the roof surface friction coefficient cloud map, and the roof z-direction-erosion rate scatter plot. The z-direction is predefined.

[0013] S7. By comparing the extracted graphics and corresponding data, high-risk areas of wind and rain erosion on building roofs are identified.

[0014] As a preferred technical solution, the parameter settings of the external flow field calculation domain meet the length requirements for turbulence development in the length direction and the requirements for raindrops to reach their terminal velocity in the height direction.

[0015] As a preferred technical solution, when meshing the external flow field computational domain model, a boundary layer mesh is added to the roof.

[0016] As a preferred technical solution, the boundary layer network has 5 or more layers.

[0017] As a preferred technical solution, when meshing the external flow field computational domain model, the curve and slit regions are densified.

[0018] As a preferred technical solution, when simulating the wind field using the Ke turbulence model, the boundary conditions at the inlet of the calculation region adopt an exponentially distributed wind profile, which is expressed as:

[0019]

[0020] In the formula, U z Let U be the wind speed at height z, U0 be the wind speed at standard height z0, and a be the preset ground roughness coefficient.

[0021] As a preferred technical solution, when simulating the wind field using the Ke turbulence model, the Simplec algorithm is used to calculate the wind field, and a second-order difference discretization scheme is selected in the solution process.

[0022] As a preferred technical solution, the simulation parameters of the discrete phase include mass flow rate, raindrop size distribution, and raindrop inlet velocity.

[0023] According to a second aspect of the present invention, a numerical simulation apparatus for wind and rain coupled erosion of building roofs is provided, comprising a memory, a processor, and a program stored in the memory, wherein the processor executes the program to implement the method described therein.

[0024] According to a third aspect of the present invention, a storage medium is provided having a program stored thereon, which, when executed, implements the method described thereon.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. This invention addresses the scenario of wind and rain coupled erosion on building roofs. It utilizes CFD software for simulation analysis, effectively identifying areas of the roof eroded by rainwater under the combined wind and rain field. Roof leakage is a major quality issue in buildings, and roof waterproofing has a crucial impact on the building's lifespan and performance. Strengthening the design of waterproofing and protective layers is essential for areas prone to rainwater erosion. Traditional design methods struggle to identify these areas. This invention, through numerical simulation, can intuitively and accurately pinpoint the areas requiring reinforcement. Traditional designs rely on experience to estimate leakage areas, which is insufficient for novel roof designs. The modular numerical simulation method of this invention is not limited by building form and can calculate easily eroded areas for various large, non-linear, and complex roofs, enabling localized reinforcement design. For health monitoring systems on some large metal roofs, sensors are added to leakage-prone areas. Previously, these areas were determined empirically; the modular numerical simulation method of this invention can quickly and efficiently identify these leakage-prone areas.

[0027] 2. The calculation and analysis method provided by this invention establishes a fluid calculation region for large nonlinear roofs based on a building model platform and computational fluid dynamics (CFD) simulation technology. It calculates the wind field based on an achievable Ke turbulence model, calculates the wind-rain coupling field using an Eulerian-Lagrange model, and calculates roof erosion through a physical model of erosion / deposition. This allows for the identification of high-risk areas for roof erosion and the implementation of enhanced design for these areas. This invention is the first to introduce numerical simulation technology into the field of roof rainwater erosion; it is the first to propose a numerical simulation calculation method for roof rainwater erosion areas, enabling enhanced waterproofing design of roofs to move beyond the stage of relying solely on experience and providing precise technical support for design. The calculation method of this invention is not limited by building form; even for complex large roofs, accurate and reliable simulation results can be obtained. The calculation method of this invention is simple and efficient; through parametric design, simulations of different wind zone conditions can be performed, quickly obtaining simulation results for multiple conditions. Attached Figure Description

[0028] Figure 1 A flowchart illustrating the method of this invention;

[0029] Figure 2 This is a schematic diagram of the CFD roof geometry model in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the computational domain model of the CFD flow field in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the mesh division of the CFD flow field in an embodiment of the present invention;

[0032] Figure 5 This is a wind speed cloud map of the flow field center profile in an embodiment of the present invention.

[0033] Figure 6 This is a vector diagram of roof wind speed in an embodiment of the present invention;

[0034] Figure 7 This is a roof dynamic pressure cloud diagram in an embodiment of the present invention;

[0035] Figure 8 This is a DPM particle trajectory diagram from an embodiment of the present invention;

[0036] Figure 9 This is a cloud map of the roof DPM erosion rate in an embodiment of the present invention;

[0037] Figure 10 This is a cloud map of the friction coefficient of the roof surface in an embodiment of the present invention;

[0038] Figure 11 This is a scatter plot of the roof z-direction erosion rate in an embodiment of the present invention. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0040] Example

[0041] like Figure 1 As shown, this embodiment provides a numerical simulation method for the coupled wind and rain erosion of building roofs, specifically including the following steps:

[0042] Step S1: Obtain the geometric information of the roof from the architectural modeling software and establish the roof geometric model.

[0043] Specifically, the geometric information of the roof, such as its curves, dimensions, and height, is obtained from architectural modeling software, and a geometric model of the roof is constructed at a moderate scale in CFD software. During this process, care should be taken to reduce unnecessary geometric elements that do not affect the simulation, in order to reduce the number of meshes in subsequent steps and lower unnecessary computational load.

[0044] In this embodiment, a symmetrical roof with a length of 20m, a width of 20m, and a tilt angle of 30° is constructed. The CFD roof geometry model is as follows: Figure 2 As shown in the figure, the directions of x, y, and z are defined.

[0045] Step S2: Extract the external flow field computational domain model of the roof geometry model.

[0046] Specifically, in CFD software, the external flow field of the roof geometry model is established, and the computational domain model of the external flow field is extracted. It should be noted that the setting of the computational domain of the external flow field should meet the requirements of turbulence development in the length direction to ensure that the flow field can be fully developed in the length direction and that raindrops can complete the complete path; in the height direction, it should meet the requirements for raindrops to reach the terminal velocity.

[0047] In this embodiment, an outer flow computational domain model with a length of 500m, a width of 80m, and a height of 70m is set. The computational domain model of the CFD flow field is as follows: Figure 3 As shown.

[0048] Step S3: Grid the external flow field computational domain.

[0049] Specifically, the computational domain for the external flow field should be meshed, preferably using structured meshes, as they offer advantages in computational speed and results. A boundary layer mesh should be added to the roof, with at least five layers. For curved and narrow regions, the mesh should be finer to increase its spatial adaptability and improve its quality.

[0050] In this embodiment, the cell size of the mesh is 1.5m. Five boundary layer meshes are inserted at the fog roof, and the mesh around the roof is densified, resulting in a final total mesh size of 300W. The mesh generation for the CFD flow field is as follows: Figure 4 As shown.

[0051] Step S4: Perform wind field simulation, set simulation parameters for the continuous phase, and when the calculated wind field converges, extract the wind speed cloud map of the flow field center profile, the wind speed vector map of the roof, and the dynamic pressure cloud map of the roof.

[0052] Specifically, simulation parameters for the continuous phase are set, including meteorological parameters such as wind speed and direction, and a realizable Ke turbulence model is used to simulate the wind field. The wind field simulation is performed with boundary conditions defined: the flow field inlet is set as a velocity inlet; the flow field outlet is set as a pressure outlet; and all other boundaries are set as walls. When calculating the boundary conditions at the inlet of the region, an exponentially distributed wind profile is used. The inlet wind velocity is defined through a user-defined function module (UDF), and the wind profile formula is as follows:

[0053]

[0054] In the formula, U z Let U be the wind speed at height z, U0 be the basic wind speed at standard height z0, and a be the preset ground roughness coefficient. Here, standard height z0 is 10m, and a is 0.16.

[0055] An achievable Ke turbulence model is adopted, the building wall is treated according to the standard wall function, the Simplec algorithm is used, and a second-order difference discretization scheme is selected in the solution process.

[0056] In this embodiment, the basic wind speed is set to 20 m / s, and the wind profile parameters are input using a UDF. The extracted wind speed cloud map of the flow field center profile is shown below. Figure 5 As shown, the roof wind speed vector diagram is as follows: Figure 6 As shown, the roof dynamic pressure cloud map is as follows: Figure 7 As shown.

[0057] Step S5: Simulate the wind-rain coupling field, set the simulation parameters of the discrete phase, and extract the DPM particle trajectory map when the calculated wind-rain coupling field reaches convergence.

[0058] Specifically, during the wind-rain coupled field simulation, once the wind field simulation has converged, a discrete phase model is inserted into the computational domain. Parameters such as mass flow rate, raindrop size distribution, and raindrop inlet velocity are set for the discrete phase. Considering the interaction with the continuous phase, a two-way coupled computational model is adopted. The wind field (continuous phase) determines the trajectory of the discrete phase, and the particles (discrete phase) simultaneously react on the wind field (continuous phase). Alternating iterations between the continuous and discrete phases are required at each time step. Once the wind-rain coupled field calculation converges, the DPM particle trajectory map is extracted.

[0059] In this embodiment, the rainfall intensity with a return period of 10 years and its corresponding raindrop spectrum are used. The extracted DPM particle trajectory map is shown below. Figure 8 As shown.

[0060] Step S6: Calculate the roof erosion amount using the erosion / accumulation model in the discrete phase, taking into account the interaction with the continuous phase. The calculation converges, and the roof DPM erosion rate cloud map, roof surface friction coefficient cloud map, and roof z-direction erosion rate scatter plot are extracted.

[0061] Specifically, the erosion / deposition model in the discrete phase was activated to calculate the roof erosion. Considering the interaction with the continuous phase, a CFD simulation of the wind-rain coupling field was performed based on the Eulerian-Lagrange multiphase flow method. The time step was divided into uniform intervals of 0.01 s, and the calculation lasted for 60 s. When the calculation reached convergence, the roof DPM erosion rate contour map, the roof surface friction coefficient contour map, and the roof z-direction erosion rate scatter plot were extracted.

[0062] The roof DPM erosion rate cloud map extracted in this embodiment is as follows: Figure 9 As shown in the figure, the surface friction coefficient contour map of the roof is as follows: Figure 10 As shown, the scatter plot of roof z-direction erosion rate is as follows: Figure 11 As shown.

[0063] Step S7: Compare the extracted graphics and corresponding data to identify high-risk areas for wind and rain erosion on the building roof. Specifically, the flow field distribution near the roof is determined and analyzed using the obtained cloud and vector maps. The movement trajectory of raindrops is observed based on the particle trajectory diagram of the discrete phase. By comparing the graphics and data, the high-risk areas for roof erosion are deduced.

[0064] Combining the extracted graphics and data, the flow field distribution near the roof was determined using the wind speed cloud map of the flow field center profile. The trajectory of raindrops was observed using the particle trajectory diagram of the discrete phase. Furthermore, the wind speed vector diagram of the roof shows that the wind speed is higher around the roof, resulting in higher terminal velocities of the raindrops and greater impact force. This conclusion is also verified by the roof dynamic pressure cloud map. Therefore, the perimeter of the roof is subjected to the strongest erosion and impact forces from the wind-rain coupled field. In addition, the roof DPM erosion rate cloud map and the roof z-direction erosion rate scatter plot show that the perimeter of the roof (especially the left and right sides and the top) is a high-risk area for rainwater erosion.

[0065] In engineering design, the waterproofing level of high-risk areas for rainwater erosion should be improved and protective measures should be increased.

[0066] Furthermore, this embodiment also provides a numerical simulation device for wind and rain coupled erosion of building roofs, including a memory, a processor, and a program stored in the memory. When the processor executes the program, it implements the aforementioned method. The processor includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or loaded from the memory unit into a random access memory (RAM). The RAM can also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus. Multiple components in the device are connected to the I / O interfaces, including: input units, such as a keyboard, mouse, etc.; output units, such as various types of displays, speakers, etc.; storage units, such as disks, optical disks, etc.; and communication units, such as network cards, modems, wireless transceivers, etc. The communication units allow the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks. The processing unit executes the various methods and processes described above, such as steps S1 to S7 in the aforementioned embodiments. For example, in some embodiments, steps S1 to S7 may be implemented as a computer software program tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps S1 to S7 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to perform methods S1 to S7 by any other suitable means (e.g., by means of firmware). The functions described above may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SOCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0067] Furthermore, this embodiment also provides a storage medium on which a program is stored, which, when executed, implements the aforementioned method. The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on a machine, partially on a machine, partially on a machine and partially on a remote machine as a standalone software package, or entirely on a remote machine or server. In the context of this invention, a computer-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0068] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A numerical simulation method for wind and rain coupled erosion of building roofs, characterized in that, Includes the following steps: S1, Obtain the geometric information of the building roof and establish the roof geometric model; S2, Extract the external flow field computational domain model of the roof geometry model; S3, perform mesh generation on the external flow field computational domain model; S4. Use the Ke turbulence model to simulate the wind field, set the simulation parameters for the continuous phase, and when the wind field calculation converges, extract the wind speed cloud map of the flow field center profile, the wind speed vector map of the roof, and the dynamic pressure cloud map of the roof. S5. Use the Euler-Lagrange model to simulate the wind and rain coupling field, set the simulation parameters of the discrete phase, and extract the DPM particle trajectory map when the wind and rain coupling field calculation converges. S6. Calculate the roof erosion amount using the erosion / accumulation model in the discrete phase and interact with the continuous phase. When the calculation converges, extract the roof DPM erosion rate cloud map, the roof surface friction coefficient cloud map, and the roof z-direction-erosion rate scatter plot. The z-direction is predefined. S7. By comparing the extracted graphics and corresponding data, high-risk areas of wind and rain coupled erosion on building roofs are obtained. Step S5 specifically includes: When the wind field simulation calculation converges, a discrete phase model is inserted into the calculation domain, and the mass flow rate, raindrop size distribution, and raindrop inlet velocity of the discrete phase are set. Considering the interaction with the continuous phase, a two-way coupled calculation model is adopted. The continuous phase and the discrete phase are alternately iterated within each time step to calculate the wind and rain coupled field until convergence, and the DPM particle trajectory map is extracted. In the two-way coupled calculation model, the continuous phase determines the motion trajectory of the discrete phase, and the discrete phase simultaneously reacts on the continuous phase.

2. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 1, characterized in that, The parameter settings of the external flow field calculation domain meet the length requirements for turbulence development in the length direction and the requirements for raindrops to reach their terminal velocity in the height direction.

3. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 1, characterized in that, When meshing the external flow field computational domain model, a boundary layer mesh is added to the roof.

4. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 3, characterized in that, The boundary layer mesh has 5 or more layers.

5. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 1, characterized in that, When meshing the external flow field computational domain model, the curves and slit regions are densified.

6. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 1, characterized in that, When simulating wind fields using the Ke turbulence model, the boundary conditions at the inlet of the computational region adopt an exponentially distributed wind profile, which is expressed as: In the formula, Let U be the wind speed at height z, U0 be the wind speed at standard height z0, and a be the preset ground roughness coefficient.

7. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 1, characterized in that, When simulating wind field using the Ke turbulence model, the Simplec algorithm is used to calculate the wind field, and a second-order difference discretization scheme is selected in the solution process.

8. The numerical simulation method for wind and rain coupled erosion of building roofs according to claim 1, characterized in that, The simulation parameters of the discrete phase include mass flow rate, raindrop size distribution, and raindrop inlet velocity.

9. A numerical simulation device for wind and rain coupled erosion of building roofs, comprising a memory, a processor, and a program stored in the memory, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1-8.

10. A storage medium having a program stored thereon, characterized in that, When the program is executed, it implements the method as described in any one of claims 1-8.

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