Unsteady Small-Gap Ground Effects.
Abstract
Fluid-dynamic problems involving bodies moving close to walls are of interest in many different contexts, and there is a considerable literature dealing with such problems. The present paper concerns itself with phenomena which can be treated on an inviscid-fluid basis, and hence has little connection with the important branch of that literature dealing with low-Reynolds-number wall effects. The small-gap regime is defined, formally, as that in which the clearance is small compared to the horizontal length scale. Flow induced by a body moving near a plane wall is analysed on the assumption that the normal distance from the wall of every point of the body is small compared to the body length. The flow is irrotational except for the vortex sheet representing the wake. The gap-flow problem in the case of unsteady motion is reduced to a nonlinear first-order ordinary differential equation in the time variable. Problems solved include airfoil starting flows and their transient wakes, and flat plates falling toward the ground.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1979
- Accession Number
- ADA068400
Entities
People
- E. O. Tuck
Organizations
- California Institute of Technology