Soft Computing Based Force Recovery Technique for Hypersonic Shock Tunnel Tests

A hemispherical model equipped with a three component accelerometer force balance has been tested in a shock tunnel at Mach 8.0 freestream conditions. A novel technique has been devised using the Artificial Neuro-Fuzzy Inference System (ANFIS) for recovering the forces experienced by the model during the experiments. Implementation of this methodology in calibration of the force balance showed encouraging agreement with the impulse forces recovered from the calibration tests. The same recovery procedure is then adopted to obtain the time history of the forces for 0 degrees and 15 degrees angle of attack experiments. The drag recovered in steady state is found to agree well with the conventional methods with minor discrimination for the lift and pitching moment. In light of the limitation of the accelerometer force balance theory due to the unaccountability of model dynamics, the force recovery technique proposed herein is found simple to implement and can be opted as a tool for prediction of the aerodynamic coefficients and force time histories