Wave propagation phenomena in three-dimensional boundary-layer flows with crossflow instability were investigated experimentally. A 10-element hot-film sensor was flush-mounted on a rotatable insert in a swept flate plate with imposed favorable pressure gradient. By means of cross-spectral analysis it was possible to obtain direction and magnitude of the phase velocity and the group velocity of the traveling instability waves, thus filling a gap in the knowledge of crossflow instability characteristics. The waves were found to propagate approximately normal to the potential streamline direction, according to linear theory. Phase velocity and the resulting wavelengths also agree satisfactorily, whereas the measured direction and magnitude of the group velocity shows significant differences.-complex wave number vector, k = (k r , &/), IA>l=27r/X goo = wind-tunnel velocity (blockage effects neglected) Re c = freestream Reynolds number, Q w • c/v S a (f) = complex spectrum of X a (t) 9 j*^ X a (t)e ~i o)t dt Tu = turbulence level Us* Vs = wall parallel velocity components, averaged in time and span wise direction (U s , V s are in the direction of x s , y s ) u s , v 5 = wall parallel velocity components of stationary instability mode u' s , v£ = wall parallel velocity components of traveling instability modes, rms values X(t) = time history record x c *y c * z = model fixed coordinate system, see Fig. 1 x s , y s , z -potential streamline fixed coordinate system, see Fig. 1 a, /3 = wall parallel components of the complex wave number vector k y 2 a b(f) -coherence function Ar? = distance between two arbitrary sensor elements A0 = phase shift between two signals 17 = sensor fixed coordinate, see Fig. 2 9 = phase angle X = wavelength v -kinematic viscosity r = wall shear stress $<» = geometric sweep angle
A symposium was held in 2003 at the University of Glasgow to celebrate the career of Professor Bryan Richards. Professor Richards was a pioneer in conducting integrated computational/experimental aerodynamic studies, and the symposium organizers took his research approach as their theme. The original (and continuing) purposes of the symposium are reproduced here because they are so essential to the overall approach of the meetings. CFD practitioners and experimentalists have a common goal of understanding aerodynamics. It is therefore surprising that often the disciplines have only a very limited interaction, which usually involves the validation of CFD. This practice supports integration at the most basic level but often there is no interaction whatsoever between the experimentalist and the CFD practitioners. This situation is unsatisfactory from many points of view including:
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