Separated bubble induced in the laminar boundary layer by a slight depression in the wall
Abstract
The existence on the surface of a flat plate of a slight hollow deformation usually will result in the creation of an elongated separated bubble. The theoretical analysis of the phenomenon is based on the integral method of Dorodnitsyn, with the concept of free interaction and, for the gradient of the velocity profile in the boundary layer, the expressions suggested by Nielsen. That enables one to complete the calculation of all of the separation zone up to the reattachment point. In the zone of expansion of the flow preceding separation, where the Nielsen theory does not apply, the calculation has been made by solving the boundarylayer equations by a finitedifference method. The characteristics of the flow thus have been computed in the entire domain of interest. The results of computation generally agree fairly accurately with the experimental measurements. This has enabled us to express laws governing the behavior of the bubble as a function of the physical data of the hollow and the main flow.
 Publication:

AIAA Journal
 Pub Date:
 September 1977
 DOI:
 10.2514/3.7416
 Bibcode:
 1977AIAAJ..15.1295P
 Keywords:

 Boundary Layer Equations;
 Bubbles;
 Flat Plates;
 Laminar Boundary Layer;
 Surface Geometry;
 Wall Flow;
 Depression;
 Finite Difference Theory;
 Pressure Measurement;
 Two Dimensional Boundary Layer;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer