Post on 30-Dec-2015
description
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