Scaling and lateral maneuverability of pitching foil in periodic freestream

Abstract

We formulate the thrust and lift coefficients using scaling laws to develop a guideline for the lateral maneuverability of a pitching foil in a periodic freestream. The scaling laws for thrust and lift coefficients of two-dimensional pitching foil in a periodic freestream are derived by considering added mass and circulatory forces. We examined the validity of scaling laws by conducting water tunnel experiments at a Reynolds number of 4.2 × 103. The key parameters are the pitch amplitude and phase difference between the periodic freestream and pitching foil. The pitch amplitude was changed from 4° to 24° with 4° increments, and the phase difference was changed from 0 to 2π with 0.25π increments. It was discovered that our scaling laws were consistent with experimental data for small pitch amplitude. By using scaling laws, we proposed guidelines to control the thrust and lift coefficients for lateral maneuver. Our guideline demonstrates that pitch amplitude can be employed to control the thrust coefficient to cancel out drag, and the phase difference is useful to control the lift coefficient without changing the adjusted thrust coefficient.