A technique is presented for carrying out relatively low-cost numerical simulations of the interaction between three-dimensional microelektromechanical systems (MEMS)- and mesoscale actuators and a laminar boundary layer. The jet-type actuators take the form of a diaphragm located at the bottom of a cavity. When the diaphragm is driven by piezoceramic, for example, it deflects, reduces the cavity volume, and drives air out of an orifice as a jet into the boundary layer. In an attempt to avoid an inflow phase into the cavity, the authors study the effects of a 'puff-like' jet produced when the diaphragm is driven by a short-duration constant force, or the cavity pressure is suddenly increased by providing air from a microvalve. The theoretical model for the actuator is based on classic thin-plate theory for the diaphragm dynamics and modified unsteady pipe-flow theory for the fluid dynamics in the orifice/nozzle leading to the boundary layer. The cavity fluid dynamics is not modeled in detail; the compressible flow in it is neglected, and the instantaneous pressure there is determined via the perfect gas law. A velocity-vorticity- method is used to compute the perturbation flowfield created in the boundary layer. This method is capable of full direct numerical simulations, but for the present results, the governing equations were linearized. The cavity and boundary-layer flowfields are linked by requiring continuity of velocity and pressure at the orifice exit. The computational methods are used to investigate such questions as the need for fully interactive computations and the differences between meso- and MEMS-scale actuators.
Numerical simulation of the interaction of microactuators and boundary layers
Numerische Simulation der Wechselwirkung zwischen einer laminaren Grenzschicht und dem von einem Mikroaktor erzeugten pulsierenden Fluidstrahl
AIAA Journal ; 40 , 1 ; 67-73
2002
7 Seiten, 5 Bilder, 20 Quellen
Aufsatz (Zeitschrift)
Englisch
FLUID DYNAMICS - Numerical Simulation of the Interaction of Microactuators and Boundary Layers
Online Contents | 2002
|STUDIES ON THE CONTROL OF SHOCK WAVE-BOUNDARY LAYER INTERACTION USING STEADY MICROACTUATORS
British Library Conference Proceedings | 2011
|