Development and Implementation of an Elastomeric Force Balance for the Evaluation of Drag Reduction Surfaces

A viscous force balance can provide rapid evaluation for a variety of drag reduction surfaces. In particular, the evaluation of riblet surfaces which refers to small scale, flow aligned ridges which have been shown to influence the turbulent boundary layer in a way which reduces viscous drag. Continued development and calibration of an elastomeric force balance to provide this capability is discussed as well as integration with a low speed wind tunnel and controller. The balance was developed using two elastomers with differing stiffness to highlight the importance of elastomer selection in regards to balance sensitivity. Evaluation of the force balance calibrated using multivariate linear regression (MVR) and an artificial neural network (ANN) demonstrate the capability to accurately predict forces acting on the balance.