Experimental measurements of the wake flow and drag of a luge sled and rider combination

The aerodynamics of a typical luge rider/sled combination were investigated experimentally. Particle image velocimetry (PIV) was used to quantify the velocity and vorticity fields in the wake of the model while a single degree of freedom force balance was used to measure the aerodynamic drag for Reynolds numbers typically seen in competition. The model was constructed to allow the investigation of trailing edge modifications that many national teams have used as drag reduction strategies. The PIV results showed that the wake was highly unsteady and turbulent. The characteristics of the wake were found to be Reynolds number dependent with earlier separation and a more significant velocity deficit found at lower Reynolds numbers. The addition of the trailing edge ramps or “cones” increased the size of the wake and the velocity deficit indicating an increased, rather than decreased drag when these sled modifications were added. Drag measurements confirmed the detrimental effects of these geometries at Reynolds numbers typical of competition although they can reduce drag at lower Reynolds numbers.