Edling, Walter H., authorCermak, J. E. (Jack E.), authorFluid Dynamics and Diffusion Laboratory, Colorado State University, publisher2019-09-172019-09-171974-04https://hdl.handle.net/10217/198115CER73-74WHE-JEC34.April 1974.Includes bibliographical references.Prepared under Office of Naval Research, Project No. NR 062-414/6-6-68 (Code 438), U.S. Department of Defense.Described are the results of an experimental study of a well-developed, turbulent boundary layer on a smooth, flat surface encountering an area of much rougher surface. The roughened area is a strip with its length extending in the direction of the mean flow but of finite width in the surface direction normal to the flow. The resulting three-dimensional flow differs significantly from previously studied cases involving step changes in roughness of infinite extent in the direction normal to the flow. Extensive experiments were carried out in a wind tunnel having a length of nearly 100 ft. (30.5 m) with a boundary layer thickness of the order of 18-20 in. (0.5 m). Pitot tube and hot-wire anemometer measurements were made of mean velocity and Reynolds stress quantities in great detail throughout the flow field. Secondary flow components were measured by a new x-wire technique permitting quick resolution of very small deflections of the mean flow vector. Considerable effort was expended to reduce and examine sources of error. The data obtained is presented both graphically and in tabular form. Analysis of the three-dimensional, turbulent boundary layer equations is carried out using the experimental results to identify significant terms. Several conclusions are reached regarding the driving mechanism of the flow, the significant flow parameters, and the effects of the three-dimensionality upon the flow as compared to the analogous two-dimensional case.technical reportsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Boundary layerLaminar flowFluid dynamicsText