Technique for the measurement of spatial vorticity distributions.
A method for measuring mean spatial vorticity content has been described for flows where the primary convective velocity (free stream) is larger than the mean crossflow components. Employing an ''X''-geometry hot-wire probe and linearized anemometer system in conjunction with a precision probe traversing mechanism, this relatively simple technique can be used to evaluate the circulation associated with various spatial contours. Errors associated with the technique are computed exactly and in simple linearized forms to illustrate its validity in a wide range of flows. A priori knowledge of the flow character and resultant careful selection of the integration paths for a given flow situation is observed to result in minimal measurement errors. Application to the problem of an isolated trailing vortex is presented as an example. Experiments at the trailing edge of a lifting wing confirm the accuracy of the method when compared with existing theories and other experimental data. The method can be extended to periodically driven unsteady flows using phase-lock techniques.
Francis
M S
MS
Mechanics Division, Frank J. Seiler Research Laboratory, U. S. Air Force Academy, CO 80840, USA.
Kennedy
D A
DA
Butler
G A
GA
D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017711:Nonlinear Dynamics; D012212:Rheology / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D013817:Thermography / Q000295:instrumentation*