Experimental Investigation of the Wake Flow and Drag of a Luge Sled*

The sport of luge is one of two Olympic sports that is timed to the 1/1000 sec. Because of the small time differences between finishers, detailed understanding of the physics is critical for success, particularly when designing equipment. Drag is an important factor of a luge run and past competitions have shown that modification of the wake flow can create significant competitive advantages. In this work we investigate the aerodynamic performance of a sled using drag measurements and high speed PIV measurements in the near wake of a luge sled. The PIV measurements reveal that the flow remains attached to the athletes body up to the neck. Two regions of reverse flow are observed on the upper and lower surfaces of the neck. The flow separates from the top of the helmet and small vortices are formed along the trailing shear layer. A low frequency, large spatial scale "flapping" of this shear layer is also observed. The wake itself was observed to be highly turbulent. The mean velocity profile in the wake showed a significant deficit in the region of the helmet, but also a significant wake deficit near to the ground plane