Hot-wire di rection-error response equations in two- dimensional flow

In order to express explicitly the effect of the angle-errors of setting a hot-wire probe in a flow field on the output of the hot-wire anemometer, approximate hotwire response series equations based on the small angleerror and weak turbulence approximations (called directionerror response equations in this paper) were derived from I-type, slanted-type and X-type hot-wire probes in twodimensional laminar and turbulent flows from a general hotwire response equation. were confirmed experimentally as being able to predict accurately the effect of the angle-errors on the output of the hot-wire anemometer as long as these angle-errors were small. It was found from these experiments and the theory that the reasoning in treating the yaw factor as a function of the yaw angle is weak and not well founded. The characteristics of the direction-error response equations for turbulent flow are discussed in terms of the order-of-magnitude theory and certain specific turbulent flows. It was found that both the magnitude and relative accuracy of the output errors due to the angle-errors predicted by the theory were dependent on the direction of the respective angle-errors and the Reynolds stresses of interest. that some of the angle-errors appear in these equations in the form of the sums of the angle-errors of specific directions regardless of laminar or turbulent flow. The direction-error response equations for laminar flow It was found from the direction-error response equations