Our customer was an educational institute who engaged in the design and development of UAVs. The objective of the project is to compare the aerodynamic performance of MAV using CFD with that of wind tunnel experiment. To simplify the mesh generation and reduce the time of simulation, the institute allowed us to ignore the landing gear in the simulation. Wind tunnel data was generated after the simulations were already completed.
Zeus Numerix carried out CFD based simulation study for 0-degree AoA case of the MAV. The geometry was not given as a CAD and had to be created using in-house surface generation tool GridZ. The surfaces adhered to the topology that will be required to generate a structured multi-block mesh that went up to 2.1 million. CFDExpert® software with the laminar flow was used to solve the aircraft as the freestream velocity was very low. The simulation was executed on a parallel 16 node Linux cluster. Good convergence was obtained and then the residual oscillated due to tip vortices.
The results of simulation compared well with experimental data with the lift deviating only 0.5% from the experimental value. The drag was under-predicted as the landing gears were not modelled in the CFD model. Good accuracy of the simulations could be attributed to the structured multi-block mesh generated on the MAV that could be controlled to have more meshes near the surfaces and tip of the wing.