Verification of the Clauser Technique in Predicting Wall Shear Stress

摘要

Results from a modified Clauser technique to predict the wall friction velocity, using a power law to model the boundary-layer velocity profile, compared well to values calculated from,the variation in the boundary-layer momentum thickness. Except for values near the leading and trailing edges of a belt, which create some unevenness on the otherwise flat wall, the values of u_ι agree well (within 2.5%) with each other. This method is similar to the study by Kendall and Koochesfahani [7], which fits the velocity data to the analytical models of Spalding [18] and Musker [19] all the way down to the wall. It should be noted that, in the present study, the least squares fit has been used in the range 5 < y~+ < 200 as opposed to being limited only to the log-linear region, giving a better estimate of the shear velocity.