Mapping and Synthesis of Random Pressure Fields

Abstract

A treatment of the mapping and synthesis of random pressure fields is presented that highlights the concepts of point, spatially and/or temporally averaged random pressure fluctuations in the context of local or integral aerodynamic loads. Space-time averaging techniques are examined that provide promising practical means to measure local random pressure fields acting on bluff structures exposed to complex flow fields and to synthesize their integral effects. Pneumatic manifolding devices utilizing a discrete or distributed matrix of pressure taps facilitate both uniform and nonuniform local spatial averaging. Alternatively, a continuous spatial averaging device utilizing a piezopolymer strip permits a similar local averaging provision. Uniform local averaging permits the evaluation of normal or lateral loads on prismatic structure, while, nonuniform local averaging facilitates expedient measurement of torsional and lateral aerodynamic loads on prismatic and cylindrical members, respectively. Synthesis of locally averaged random fields permits evaluation of mode-generalized aerodynamic loads. The design of pneumatic manifolding devices and their calibration procedures are presented. An example of torsional aerodynamic loads on prismatic structures exposed to simulated atmospheric flow conditions in boundary layer wind tunnels is presented.