The Heated Surface Probe for Measuring Shear Stress at the Wall in Laminar Boundary Layers


  • Zeev Rotem

    1. Department of Mechanical Engineering, University of British Columbia, Vancouver, B. C.
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    • This work was carried out while the author held a Research Fellowship at the Department of Chemical Engineering, Stanford University, Stanford, Cal., U. S. A.


A heated-surface instrument for the measurement of wall shear-stress was apparently first used by Ludwieg (2). Its main advantages over the more common Stanton tube is the comparatively very minor disturbance of the flow, even within the wall boundary layer, caused by the instrument, and its high sensitivity. The present paper describes modifications to Ludwieg's original probe, its use with a masstransfer process, and gives a more reliable analysis of its performance.


L'article décrit la construction et l'essai d'un instrument qui mesure indirectement l'effort en cisaillement d'un fluide sur une parois fixe. On utilise un élément de la parois en l'échauffant, et la dissipation de chaleur par convection forcée serf comme mesure de l'effort en cisaillement à la parois. Une variante de l'instrument est basée sur l'effet de convection de masse dans un système électrochimique. Une théorie détaillée de l'instrument est donnée.