Benefit is claimed under 35 U.S.C 119(a)-(d) to Foreign Application Serial No. 4168/CHE/2013, filed in INDIA entitled “SYSTEM AND METHOD FOR BI-DIRECTIONAL COUPLING OF FINITE ANALYSIS SOLVERS” by AIRBUS INDIA OPERATIONS PVT. LTD., filed on Sep. 17, 2013, which is herein incorporated in its entirety by reference for all purposes.
Embodiments of the present subject matter relate generally to finite analysis, and more particularly to coupling of finite analysis solvers for multi-disciplinary simulations.
Finite analysis or numerical solvers that provide solutions to specific problems are commercially available. For example, finite analysis solver “Fluent®” is available for Computational Fluid Dynamics (CFD) and “Ansys Mechanical®” is available for Finite Element Analysis (FEA—Mechanical and Thermal. Typically in industrial applications, it is required to sequentially couple two different finite analysis solvers for multi-disciplinary simulations. For example, CFD-FEA coupling may be required for fluid structural interaction (FSI) applications. In such a coupled simulation scenario, one of the finite analysis solvers may be used as a leading finite analysis solver. In the example of CFD-FEA coupling, “Fluent®” may be used as the leading finite analysis solver for CFD analysis and “Ansys Mechanical®” may be used as the second finite analysis solver for FEA-Thermal analysis. In this case, the output data from the CFD solver may be used by a thermal model in “Ansys Mechanical®” as new loads or boundary conditions and vice versa. Generally, this process continues till the sequential coupling of finite analysis solvers/simulation is performed for the entire computational/simulation period.
For strongly coupled and time-varying phenomena, it is required to perform transient or time-varying computations while mapping data back and forth from one finite analysis solver to another iteratively. Multiple coupling iteration loops may be required between the two finite analysis solvers as they progress in time.
Further, the existing solutions require the time instances at which coupling needs to be performed and the time-step sizes of the coupling steps to be fixed. However, for some duration during simulation, the two finite analysis solvers may need to be coupled as frequently as possible to improve the computational efficiency; while for remaining time duration, the finite analysis solvers may have to be coupled with reduced frequency based on user requirements to reduce computational costs.
Furthermore for an optimized simulation activity, the two finite analysis solvers may require significantly different mesh configurations (for example, mesh size and element type) for different domains. The finite analysis solvers may also have different computational hardware or platform requirements. Therefore, the finite analysis solvers may need to run on different servers, different operating systems and/or different processors at different geographical locations while communicating with each other to transfer data. This may not be always be possible to implement with some existing solutions.
In addition, existing solutions may require using fixed and/or default boundary conditions, such as functions/parameters, which may be inaccurate. The computation of these boundary conditions may be based on some fixed definition, which may not be applicable for all generic scenarios. Also, the existing solutions may not allow user defined functions (UDFs) and criteria/definitions for the boundary conditions to be added as plug-ins in the program structure of the two finite analysis solvers.
A system and method for bi-directional coupling of commercially available finite analysis solvers is disclosed. According to one aspect of the present subject matter, the method for bi-directional coupling of finite analysis solvers includes forming a first finite analysis model and a second finite analysis model, using user defined first and second boundary conditions respectively in a first finite analysis solver and a second finite analysis solver. Further, a task scheduling service (TSS) is configured based on the first and second finite analysis solver dependent boundary conditions for the first finite analysis solver and the second finite analysis solver. Furthermore, the second finite analysis solver dependent boundary conditions are computed by the first finite analysis solver, by performing finite analysis on the first finite analysis model, based on the first boundary conditions and frequency of coupling. Furthermore, the computed second finite analysis solver dependent boundary conditions are transferred by the TSS to the second finite analysis solver, along with a control signal to the second finite analysis solver. Furthermore, upon receipt of the control signal from the TSS, the second finite analysis solver computes the first finite analysis solver dependent boundary conditions by performing finite analysis on the second finite analysis model, based on the second boundary conditions and frequency of coupling. Furthermore, the TSS transfers the computed first finite analysis solver dependent boundary conditions to the first finite analysis solver, along with a control signal to the first finite analysis solver. Furthermore, these steps of computing, transferring, computing and transferring are repeated until a convergence is achieved between the first and second finite analysis solvers.
Also, a customized solver specific service is configured for the first finite analysis solver and another customized solver specific service is configured for the second finite analysis solver to monitor the tasks performed by the first finite analysis solver and the second finite analysis solver. These solver specific services, along with the task scheduling services removes any limitations in currently existing techniques/commercial software as described earlier.
According to yet another aspect of the present subject matter, a non-transitory computer storage medium for coupling commercially available finite analysis solvers having instructions that, when executed by a computing device, causes the computing device to perform the method described above.
These and other advantages of the present subject matter will be apparent from the accompanying drawings and from the detailed description that follows. The system and method disclosed herein may be implemented in any means for achieving various aspects.
Various embodiments are described herein with reference to the drawings, wherein:
The drawings described herein are for illustration purpose only and are not intended to limit the scope of the present disclosure in any way.
A system and method for bi-directional coupling of finite analysis solvers is disclosed. In the following detailed description of the embodiments of the present subject matter, references are made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present subject matter. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present subject matter is defined by the appended claims.
The terms “frequency of coupling” and “coupling time-step size”, “are used interchangeably throughout the document. The terms “time-step” and “load step size” are specified as part of first and second boundary conditions and are smaller than the “coupling time-step size”. The terms “solver dependent boundary condition”, “new data”, “load”, “file load” are also used interchangeably throughout the document. The terms “finite analysis solver” and “FA solver” are also used interchangeably throughout the document. The terms “solver specific service”, “customized solver specific service”, “SSS” are also used interchangeably throughout the document.
According to another embodiment of the present subject matter, the memory module 112 inside the first computing system 102 contains instructions for the operation of the customized solver specific service 122 inside the first computing system 102. Furthermore, the memory module 162 inside the second computing system 106 contains instructions for the operation of the customized solver specific service 172 inside the second computing system 106. Furthermore, the memory module 142 inside the third computing system 104 contains the instructions for the operation of the TSS 150 in the user computing system 104. The execution of instructions contained in its memory module 112 by the CPU 110 of the first computing system 102, the execution of instructions contained in its memory module 162 by the CPU 160 of the second computing system 106 and the execution of instructions contained in its memory module 142 by the CPU 140 of the third computing system 104 results are explained in detail with reference to
The SSS 122 for the first FA solver 120 is customized for the first FA solver 120 and the tasks performed by the first FA solver 120 is monitored by the SSS 122 implemented in the first computing system 102. The first FA solver 120 is usually referred to as a lead solver. Example first FA solver 120 includes a CFD solver, such as Fluent®. The SSS 172 for the second FA solver 170 may be customized for the second FA solver 170 and the tasks performed by the second FA solver 170 is monitored by the SSS 172 implemented in the second computing system 106. Example second FA solver 170 includes a FEA-Thermal solver, such as Ansys Mechanical®. The TSS 150 implemented in the third computing system 104 controls the coupling between the two FA solvers and also provides the control signal to the two FA solvers to signal the availability of solution data (or load data for other solver). The user may specify time instances of coupling and time-step sizes of coupling for the two FA solvers in the SSS plug-ins. Flexibility may be added to have variable coupling time-step size. Further, the user defined inputs to the first and second FA solvers are specified in respective SSSs. The third computing system 104 checks the availability of new or customized data and transfers available data or other solvers, and signals to the other FA solvers to continue the simulation
The use of TSS 150 allows the FA solvers to be executed on different systems or different operating systems or different processors. In a case when one FA solver takes significantly longer time than the other FA solver to perform its computations, that FA solver can be executed on a system with parallel processors to speed up its computations. Also, when people of different groups or departments work on different types of finite analysis, they may need to run their respective FA solvers at different geographical locations as well. Also, for optimized simulation activity for the individual solvers, the two FA solvers may require significantly different mesh (difference typically in mesh size and element type) for their respective domains. The FA solvers may also have different computational hardware or platform requirements. Therefore, the FA solvers may need to run on different servers or different operating systems or different processors at different geographical locations while communicating with each other to transfer the solution data. The use of TSS allows all these possibilities. The TSS 150 continuously checks whether one of the FA solvers has generated the solution data or load files for the other FA solver. When load files have been generated by one of the FA solvers, the generated load files are transferred by the TSS 150, from the location or file system of that FA solver, to the location or file system of the other FA solver. The TSS 150 then signals the other FA solver that new load files have been transferred.
The use of customized solver specific service for the two FA solvers provides the advantage of any customized definition of the loads to be applied to or calculated by the two FA solvers to improve the accuracy of mapping between the two FA solvers. In some embodiments, mapping of loads based on user defined criteria or plug-in and performing coupling are performed irrespective of geographical/platform location. In a specific example, the first FA solver 120 (CFD solver Fluent®) writes the solution data to be used by a thermal model in the second FA solver 170 (FEA solver Ansys Mechanical®). The solution data can be in any form such as convective loads (heat transfer coefficient-reference temperature combination (or HTC-Tref combination) or Heat Flux or Heat Rates) on the wetted interfaces for the thermal model in Ansys Mechanical®, pressure or force data causing displacement of nodes in a structural model, or temperature data to be used for thermal stress analysis in a finite element (FE) model. In turn, the second FA solver 170 (Ansys Mechanical®) writes the solution data to be used by a CFD model in the first FA solver 120. The solution data can be in any form such as temperature loads on the wetted interfaces, or nodal displacements, or heat rate or flux to be used by the CFD model in the first FA solver (Fluent®). Accuracy in coupling process can be improved by using customized definition of solution data like HTC and Tref as specified by the user.
Referring now to
Referring now to
At step 302, a first finite analysis model and a second finite analysis model are formed using first and second boundary conditions in the first FA solver 120 and the second FA solver 170, respectively. The setup of the first FA solver 120 and the second FA solver 170 is performed by the respective customized solver specific service (SSS) interfaces as explained earlier with reference to
The first and second boundary conditions include user defined values for time instances at which coupling is to be performed and the size of coupling time-steps, customized solver dependent boundary conditions, such as UDF, which is the solution data or load files coming from the other solver, customized solver independent boundary conditions, which are inputs required for performing simulation on the two finite analysis models, and customized solver dependent user defined functions and criteria.
At step 304, configures a TSS based on the first and second FA solver dependent boundary conditions for the first finite analysis solver and the second finite analysis solver. The tasks performed by the TSS have been explained earlier with reference to
At step 306, the second FA solver dependent boundary conditions are computed, by performing the finite analysis on the first finite analysis model based on the first boundary conditions and frequency of coupling. The tasks performed by the first FA solver are monitored by the customized solver specific service (SSS) 122 for the first FA solver which has been explained earlier with respect to
At step308, the second FA solver dependent boundary conditions (solution data or file loads) are transferred by the TSS to the second FA solver along with a first control signal to the second FA solver upon computing the second FA solver dependent boundary conditions.
At step 310, the first FA solver dependent boundary conditions are computed by the second FA analysis solver, by performing the finite analysis on the second FA model using the computed second finite analysis solver dependent boundary conditions, based on second boundary conditions and frequency of coupling upon receipt of the first control signal from the TSS. The tasks performed by the second FA solver 170 is monitored by the customized solver specific service (SSS) 172 for the second FA solver 170 which has been explained earlier with respect to
At step 312, the first FA solver dependent boundary conditions (solution data or file loads) are transferred by the TSS to the first FA solver, along with a second control signal to the first FA solver upon computing the first FA solver dependent boundary conditions.
Steps 306 to 312 are repeated automatically until a convergence is achieved between the first and second FA solvers.
The interaction between the customized solver specific service (SSS) of the two FA solvers and the TSS is responsible for the execution of process steps 302 to 312. This will now be explained in more detail with reference to
Referring now to
The use of SSS permits the coupling process explained above to be applied for any type of FA solvers for performing different types of analysis (for example fluid-structural coupling, thermal-mechanical coupling, etc) provided the FA solvers allow customization, using command line approach or scripting in addition to GUI (graphical user interface) based approach, to perform specific tasks as desired by the user.
The above bi-directional coupling technique provides a significantly improved accuracy with respect to uncoupled standalone simulations. Further, the above technique provides a robust coupling process to accurately predict the performance of a system and a completely automated coupling process after initial setup. Furthermore, the above technique facilitates execution of the solvers on different systems or operating systems or processors at different geographical locations. In addition, the above technique allows performing bi-directional coupling at different time instances with varying time-step sizes. Also, the above technique allows use of customized definition of loads to improve the accuracy of mapping. Moreover, the above technique allows mapping of different kinds of loads for different solvers or for different types of finite analysis and further allows performing of both transient and steady state simulations.
Although the coupling method of the present subject matter is illustrated with two FA solvers, it can be applied to any number of FA solvers running on the same or different systems.
Although certain methods and systems have been described herein, the scope of coverage of this application is not limited thereto. To the contrary, this application covers all methods and systems fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.
Number | Date | Country | Kind |
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4168/CHE/2013 | Sep 2013 | IN | national |