Mike Gaster (m.gaster@qmul.ac.uk)

Boundary layer perturbations created by various boundary value excitations

),(),,( txvtxu to be imposed on the wall

Velocity perturbations created by a periodic source

Phase locked velocity fluctuations on a smooth plate excited by a periodic point source

C Calculation Measurement

Perturbation Created by u(0) = δ(x)

We can choose appropriate boundary values to model various physical situations:-

jets issuing from a slit or from a point set at an angle to the flow – either steady or unsteady,

an isolated bump, 2-D or 3-D, steady or unsteady,

a periodic roughness ripple, random roughness,

moving roughness.

Transfer function for active control.

Skin friction from a periodic point source

Re = 1000 Free-stream velocity =12.6m/s

Frequency = 150 Hz

Fast-nearfield.exeFast-nearfield.exe

Flow over a sinusoidal ripple

Phase locked velocity fluctuations on a smooth plate excited by a periodic point source

C Calculation Measurement