Review of Hot-Wire Anemometry Techniques and the Range of their Applicability for Various Flows

A review of hot-wire anemometry was made to present examples of past work done in the field and to describe some of the recent and important developments in this extensive and ever expanding field. The review considered the flow regimes and flow fields in which measurements were made, including both mean flow and fluctuating measurements. Examples of hot-wire measurements made in the various flow regimes and flow fields are presented. Comments are made concerning the constant current and constant temperature anemometers generally in use and the recently developed constant voltage anemometer. Examples of hot-wire data obtained to substantiate theoretical results are presented. Some results are presented to compare hot-wire data with results obtained using other techniques. The review was limited to wires mounted normal to the flow in non-mixing gases. † Currently Engineer at Computer Science Corporation, Laurel, MD 20707 Also, Consulting Research Engineer at Advanced Engineering, Yorktown, VA 23693 NOMENCLATURE a a 1 4 − constants in equation (47) a speed of sound A B , constants in equation (24) A A 1 3 − constants in equation (18) b b 1 3 − order of q in equation (47) B B 1 5 − constants in equation (19) ( ) ′ A To Lkt ′ Aw overheat parameter, ( ) 2 ∂ ∂ log log R I w h ( ) ′ B To 2 L k c r t p w π cp specific heat at constant pressure cv specific heat at constant volume cw specific heat of wire d wire diameter of mesh ( ) d dt rate of change of quantity ( ) with respect to time dc diameter of cylinder di diameter of jet dw diameter of wire ′ e instantaneous voltage across the wire E mean voltage across the wire Eout anemometer output voltage ′ E finite-circuit parameter, ( ) ( ) 1 1 2 − + ′ ε ε Aw f frequency