Verification and validation of CgWind: a high-order accurate simulation tool for wind engineering

This paper presents the verification and initial validation of CgWind, a new, high-fidelity, large eddy simulation code for wind engineering applications. CgWind utilizes fourth-order accurate spatial discretizations of the incompressible Navier-Stokes equations on composite, structured grids to achieve both high efficiency and high spatial resolution without sacrificing the ability to model complex and moving geometries. Computational models such as CgWind consist of complex numerical algorithms and software whose correctness must be verified prior to use as a mathematical model for practical simulations. The process of verification demonstrates that a numerical model is implemented correctly and confirms the theoretical properties (stability and accuracy) of the discrete approximations of the continuous mathematical model. After verified successfully, validation then determines the suitability of the mathematical model to capture the relevant physical phenomena for problems of interest. Rigorous verification has been built into the development of CgWind, and verification of accuracy and convergence has been demonstrated. The code is now undergoing validation by comparison to experimental data.