Finite volume method for subsonic wind tunnel design

• Main Authors: Mohammed, Rosul A., Farge, Talib Z., Almukhtar, Ali H.
• Format: Conference Proceeding
• Language: English
• Subjects: Algorithms; Computational fluid dynamics; Convergence; Damping; Dependent variables; Diffusers; Finite volume method; Flow separation; Fluid flow; Mass flow rate; Mathematical models; Random variables; Subsonic wind tunnels; Two dimensional flow
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0208696

The process of creation and evaluation of designs has been a lot easier and faster using computational fluid dynamics (CFD), which has played an important role in limiting the need to do a lot of model making, or at least, minimizing the number of experimental models needed. The goal of this study was to determine the best design possible for a subsonic wind tunnel by presenting 3 models with different wind tunnel geometries. The fluid flow inside the whole wind tunnel was represented by mathematical models and computed using (CFD). The governing Euler’s equations were solved using an explicit finite volume algorithm by assuming the flow to be 2D, unsteady, and inviscid using a finite volume cell structure with flow properties saved at cell centers. Using MATLAB, the computational steps were programmed and executed, presenting an approach to compute the flow properties (u, v, ρ, and p) and evaluating the value of the mass flow rate ratio (FMR), which gives an indication of the results accuracy after an iterative process, which gives the freedom to make the initial guess of the dependent variables completely random as the final solution is independent of the initial guess. Stability and convergence of the solution were confirmed by using the damping terms and relaxation terms. Finally, Case 3 was chosen as it gives a better convergence speed and it represents a more suitable CFD solution than the other cases. The flow angle at the diffuser’s wall was set at less than or equal to 10 to prevent the flow separation in the diffuser section.