Characterizing dynamics of a Translating Rotating Cylinder (TRC) as an equivalent vortex model for vortex-boundary interactions

A novel experimental approach for imposing a translating pressure perturbation on a boundary layer using a Translating Rotating Cylinder (TRC) of diameter, D is presented. The TRC serves as a surrogate for a translating vortex often seen in unsteady aerodynamic flows. The current experiments characterize the wall-pressure signature imposed by the system and build the overall profile shape and peak-pressure in an equivalent vortex model. The pressure profile on the wall was measured with 9 spanwise pressure ports measuring high-speed pressure and PIV in the stream-wise – wall-normal plane. Pressure fields were also estimated from the PIV flow fields via an omnidirectional line integration method developed by Zigunov and Charonko (Meas. Sci. Technol. 35 065302). The wall pressure profile measured by the pressure taps and the PIV to pressure calculations were in good agreement across a range of parameters providing a comprehensive picture of the dynamics. The induced pressure profile on the wall is a function of three variables: height, h , translation velocity, c and rotational speed, ω. The relationship between these variables and the imposed pressure perturbation f(h/D, ωD/c, cD/ν), is characterized, and a dynamical vortex-equivalent model is proposed to predict the wall pressure profile for the nondimensional variables.