No abstract

Transitional flow past a circular cylinder in the lower subcritical regime (Re = 3900) has been analysed using Large Eddy Simulation (LES) coupled to Smagorinsky and dynamic sub grid scale models. These simulations have been carried out using a parallel multiblock structured finite volume code which is based on SIMPLE algorithm. The predictions are validated against detailed measurement data for mean as well as turbulence quantities. The present LES prediction in general agree reasonably well with the measurement data in the near wake region but deviates from the measurement data in the far wake region which may be due to the coarse resolution of the grid in this region. The influence of the SGS model on mean flow quantities as well as on the flow structures are also discussed.

Turbulent flow past low aspect ratio (AR) thin wing used for two different MAV (Micro Air Vehicles) configurations viz. Black Kite and Golden Hawk has been carried out in order to analyze their aerodynamic characteristics. The Reynolds (Re) number for these two wings based on the root chord are 2.4×10 5 and 1.72× 10 5 respectively. These simulations have been carried out using the in-house flow solution code to solve the Unsteady Reynolds Averaged Navier Stokes (URANS) equations coupled to different turbulence models. The standard k-ε model has been used to simulate the turbulence for the Black Kite wing. The influence of three different turbulence models (standard k-ε, SA and SST) in predicting the aerodynamic coefficient has been studied for the Golden Hawk configuration. In the present study the aerodynamic characteristics computed for the two wing configurations are compared with the CSIR-NAL experiments. The cross flow patterns and the tip vortex for the Golden Hawk wing are presented and discussed.

No abstract

No abstract