Re-examination of compliant wall experiments in air with water substrates. [for drag reduction

Previous investigations of possible drag reduction using compliant waves have been reexamined. In an attempt to duplicate the earlier experiments, standing waves were observed to form on the compliant surface as the freestream velocity was increased from 15 m/sec to 30 m/sec. These waves resembled sine waves. The results obtained suggest a possible explanation for the large apparent drag reductions obtained previously with compliant walls (with liquid substrates).