Streamwise normal Reynolds stress variations of fully developed turbulent pipe flow responds to rough wall disturbances

Fully developed pipe flow is disturbed by rough wall section and measurements are carried out in the downstream of rough wall section. Emphasis is placed on the response of the flow to different types (d- and k-type) of rough wall. Larger turbulent bore of k-type flow is found into still increase while providing longer rough wall section and d-type flow also seemly to increase but comparatively small in magnitude. The response function of flow changes according to rough wall length and internal boundary layer thickness but weakly depends on type of roughness. The edge of internal boundary layer is examined by pointing out the intersection of disturbed and undisturbed of normal Reynolds stress curves. Compare to the other estimation methods of internal boundary layer thickness, thicker and almost same trend of development are found in present method.