Viscous damping theory based recovery algorithm for force measurement in hypersonic flow regime

Abstract

Prediction of aerodynamic forces is challenging task ahead aero-dynamists, specifically in the hypersonic flow regime. As per available literature in this field, there is a scarcity of recovery techniques to predict the applied aerodynamic load from a known response. Therefore, a Viscous Damping based novel algorithm is proposed for recovery of the unknown force from known response. Novelty of the presently proposed Viscous Damping technique resides in the fact that it is based on the physical principles those govern the motion of model-balance assembly. On the other hand, the contemporary techniques are data driven and hence provide approximate solution to the problem. For considering applicability of this technique, a bicone-shaped test model is designed and fabricated. This test model, integrated with an accelerometer force balance assembly, is calibrated using multiple point loads. Successful calibration experiments are then followed by experiments in IITB- Hypersonic Shock Tunnel (HST) at 0° Angle of Attack (AOA). Spike is also mounted on the model during force measurement experiments to assess the sensitivity of the Viscous Damping based technique. This technique has shown excellent agreement in force recovery with the conventional accelerometer force balance theory for the calibration as well as shock tunnel experiments. Therefore, presently proposed method is noticed to provide a definitive recovery and it is also seen to be sensitive since it has precisely recovered the reduced drag force in the presence of spike.