revision received 20 September 2001; accepted for publication 15 October 2001. This material is declared a work of the US Government and is not subject to copyright protection in the United States. Copies of this paper may be made for personal or internal use, on condition that the copier pay the $10.00 per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923; include the code 0748-4658/02 $10.00 in correspondence with the CCC. ค Research Physicist, Aerodynamics Branch. Senior Member AIAA.† President, 6801 Benjamin Street. Senior Member AIAA.‡ Research Physicist, Aerodynamics Branch. Senior Member AIAA.

2= integration variable ต= lock-in angle ธ= radius of curvature น= coeffi cient of friction ฝ= diameter of circle ม= orientation of R ร= orientation of r ร 0= initial value of ร k= absolute value 0= d./= d ม ข= d./= dt hi= average value ฃ= vector product