Unsteady Pressure Measurement of Transonic Buffet on NASA Common Research Model

Experimental investigation of transonic buffet was conducted in JAXA 2m×2m transonic wind tunnel in order to obtain the validation data for unsteady computational fluid dynamics and to clarify the buffet phenomena of an 80% scaled NASA common research model. Unsteady pressure distributions on the two lines of the main wing were successfully measured on the transonic buffet condition. Mach number of the uniform flow was 0.85. Reynolds numbers based on the reference chord length were 1.515×10 and 0.947×10. The shockwave oscillation on the wing can be classified into three regions, a small oscillation region without separation, an oscillation region with bump in the power spectrum, and a large oscillation region with broadband power spectrum. The Strouhal number based on the bump peak frequency was about 0.3. The cross-correlation and the phase analysis revealed that the pressure fluctuation of the bump frequency propagated from the wing root side to the wing tip side.