Solver
The solver resolving time constitutes of two stages
(a) Stage 1: 20 s solution time
(b) Stage 2: 10 periods
In Stage 1, the simulations have been run for 20 seconds (Solution time 1 second represents 50,000 inner iterations of calculation). The purpose is to make sure that the flow solution is in good convergence. Convergence means the solutions obey the conservation equations well and is usually observed and verified through the residuals which is expected to be close to zero. In this project, residuals for all simulations have reached to an extremely small level after 20-second solution time, which means the solutions of the simulations are in good convergence and the initial settings are effective.
In Stage 2, the simulations are run for 10 periods. This period differs for different aerofoils at different angles of attack. As the flow is defined as implicit unsteady, the flow is varying with time and the flow properties like the lift, the wall shear stress, and etc. show periodic signs. In this project, the period is determined using the periods of the lift coefficient. The purpose of this second stage is to collect the useful data such as wall shear stress and lift and drag coefficients by the software itself. The reason for collecting data in the second stage is because the convergence has been proved by the previous stage and the data is considered as effective and convincing.
(a) Stage 1: 20 s solution time
(b) Stage 2: 10 periods
In Stage 1, the simulations have been run for 20 seconds (Solution time 1 second represents 50,000 inner iterations of calculation). The purpose is to make sure that the flow solution is in good convergence. Convergence means the solutions obey the conservation equations well and is usually observed and verified through the residuals which is expected to be close to zero. In this project, residuals for all simulations have reached to an extremely small level after 20-second solution time, which means the solutions of the simulations are in good convergence and the initial settings are effective.
In Stage 2, the simulations are run for 10 periods. This period differs for different aerofoils at different angles of attack. As the flow is defined as implicit unsteady, the flow is varying with time and the flow properties like the lift, the wall shear stress, and etc. show periodic signs. In this project, the period is determined using the periods of the lift coefficient. The purpose of this second stage is to collect the useful data such as wall shear stress and lift and drag coefficients by the software itself. The reason for collecting data in the second stage is because the convergence has been proved by the previous stage and the data is considered as effective and convincing.