Download Full Text (24.1 MB)


National Advisory Committee for Aeronautics Technical Note 4102

Information collected from the referenced literature and supplemented by new solutions is presented on the flow characteristics - velocity field, pressure drop, and friction - for steady, fully developed laminar flow through a duct consisting of two parallel walls, for flow through tubes with circular cross section, and for boundary-layer flow over infinite wedges. It is assumed that the fluid either is ejected through the porous walls into the main flow or is removed from the main flow by suction. The properties of the fluid both in the main flow and in passing through the porous walls are assumed constant, identical, and incompressible. In order to determine the extent to which the boundary conditions imposed on the flow by the various geometries influence the flow characteristics, dimensionless parameters common to both channel and boundary-layer flow (channel flow is flow with bounding walls, e.g., a tube) were developed. By using these parameters to compare the various flows, the flow on surfaces with fluid ejection as well as on solid surfaces was found to depend mainly on the local boundary- layer thickness, on the pressure gradient in main -flow direction, and on the ejection rates. Whether the viscous flow is confined in a channel or unconfined in a boundary layer is of secondary importance . This finding forms the basis for general correlations and shows the conditions under which data on channel and boundary- layer flow are interchangeable; it also should be

Publication Date


Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


National Advisory Committee for Aeronautics


Washington DC


Physical Sciences and Mathematics

Velocity and Friction Characteristics of Laminar Viscous Boundry-Layer and Channel Flow over Surfaces with Ejection or Suction