Numerical Modelling on Wind Flow with Innovative Grid Arrangement
應用新型混合網格技術于風流動數值模擬
Student thesis: Doctoral Thesis
Author(s)
Related Research Unit(s)
Detail(s)
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| Award date | 18 Nov 2024 |
Link(s)
| Permanent Link | https://scholars.cityu.edu.hk/en/theses/theses(5ae5cee2-5229-41da-84e1-6864159e1164).html |
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| Other link(s) | Links |
Abstract
In this thesis, a systematic exploration of numerical techniques for modelling turbulent wind flow is presented. The mathematical modelling of turbulent wind flow and methods of discretization of governing equations into algebraic equations for numerical solution are reviewed.
Recognizing the limitations of the unstructured tetrahedral grid and structured hexahedral grid, a hybrid grid strategy is put forward specifically tailored for atmospheric boundary layer flow by combining the advantages of both structured grid and unstructured grid. This strategy aims to strike a balance between capturing the intricate details of the flow and minimizing the computational burden associated with an overwhelming number of grids.
To enhance the efficiency of the hybrid grid arrangement, novel and inventive techniques are proposed to reduce the number of grids used for simulation and to shorten simulation time with satisfactory grid quality. These techniques are designed to optimize the distribution and configuration of the grids with octree-based cartesian grid and to constrain the tetrahedral grid very close to the building surface. A self-developed grid generation algorithm is introduced for practical implementation on this novel hybrid grid method, offering a tailored and efficient solution to hybrid grid generation. The hybrid grid algorithm characterizes highly automatic meshing process with minimized user inputs.
To validate the proposed numerical simulation framework with hybrid grid, a case study is conducted on a building cube using various turbulence models including RANS and LES models. The simulation results are meticulously compared with experimental measurement data, providing a rigorous assessment of the accuracy and reliability of the developed hybrid grid generation approach.
Through the present study, an efficient and accurate hybrid grid approach for modelling turbulent wind flow has been established, offering valuable insights and a practical solution to a wide range of applications related to wind flow study.
Recognizing the limitations of the unstructured tetrahedral grid and structured hexahedral grid, a hybrid grid strategy is put forward specifically tailored for atmospheric boundary layer flow by combining the advantages of both structured grid and unstructured grid. This strategy aims to strike a balance between capturing the intricate details of the flow and minimizing the computational burden associated with an overwhelming number of grids.
To enhance the efficiency of the hybrid grid arrangement, novel and inventive techniques are proposed to reduce the number of grids used for simulation and to shorten simulation time with satisfactory grid quality. These techniques are designed to optimize the distribution and configuration of the grids with octree-based cartesian grid and to constrain the tetrahedral grid very close to the building surface. A self-developed grid generation algorithm is introduced for practical implementation on this novel hybrid grid method, offering a tailored and efficient solution to hybrid grid generation. The hybrid grid algorithm characterizes highly automatic meshing process with minimized user inputs.
To validate the proposed numerical simulation framework with hybrid grid, a case study is conducted on a building cube using various turbulence models including RANS and LES models. The simulation results are meticulously compared with experimental measurement data, providing a rigorous assessment of the accuracy and reliability of the developed hybrid grid generation approach.
Through the present study, an efficient and accurate hybrid grid approach for modelling turbulent wind flow has been established, offering valuable insights and a practical solution to a wide range of applications related to wind flow study.
- CFD, grid generation, hybrid grid, wind simulation, turbulence model, validation, OpenFOAM
