Implementation of a turbulence model for the Vortex Cloud Method

The purpose of this work is the development and validation of a Large Eddy Simulation (LES) model for the Aerodynamic’s Section at ESEIAAT in-house Vortex Cloud Method (VCM) fluid mechanics solver. The previous version of the program allowed for a less computationally expensive way to model 2D flow where separation or viscosity effects are important. The addition of a LES subroutine to this program allows studies in conditions where turbulence plays an important role. The subroutine was initially intended to be developed for a Fortran version of the ESEIAAT solver, which was optimised for performance. However, some problems with the Fortran version appearing at the testing stage required a switch to an older MATLAB version. The subroutine was rewritten in MATLAB code and the MATLAB version of the code adapted to accommodate it. Unfortunately, the MATLAB program had a much greater computational cost, which entailed a reduction of the scope of the validation of the program. Consequently, only preliminary validation of the program is carried out in the present work, comparing its performance with bibliographic data, both numerical and experimental. The results obtained are satisfactory and showed that the new LES version of the solver matches closely the results obtained by other similar programs. Despite this, there are still some aspects of the methodology that need more testing and adjustments before it could have full research use. Some questions also arose regarding the adequacy of the implemented LES turbulence model that are discussed in this work. This work has also highlighted the need of properly adjusting the program to each flow situation and has provided information on the different variables to be adjusted. Both physical and numerical (program stability and computational cost) considerations have to be taken into account for a successful adjustment.