The Effects of Unsteady Potential Flow on Heated Laminar Boundary Layers in Water: Flow Properties and StabilityThe effects of unsteadiness and the stability of boundary-layer flows as governed by the Orr-Sommerfeld equation are discussed. The condition required for validity of the quasisteady approximation of governing flow equations is that the ratio of diffusion time to flow time should be small. It is also shown that criteria for validity of the quasi- steady approximation of the Orr-Sommerfeld equation are based on modifications of this ratio, and are not nearly as stringent. Examples of heated wedge flows in water that are presented and discussed show the profound effect of even slowly varying unsteadiness on both laminar boundary-layer flow and its stability. (Author). |
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a²p acceler Advanced Research Projects adverse pressure gradient boundary layer accommodates boundary-layer stability crit critical layer critical Reynolds number decrease Defense Advanced Research differential equations displacement thickness effects of unsteadiness favorable pressure gradient flat-plate Flow over Heated Fluid Mechanics freestream velocity gradient and surface heat and pressure heat transfer heated wedge flows Laminar Boundary Layer layer flow Layers in Water mild unsteadiness nearly quasi-steady flow neutral stability Nusselt number order of magnitude ordinary differential equations Orr-Sommerfeld equation parameter with wall Potential Flow quasi-steady approximation quasi-steady parameter Rand Rand Corporation ratio of diffusion Research Projects Agency SHAPE FACTOR skin friction solution stability analysis stability characteristics Stability Theory surface overheat temperature time-dependent U₁ U2 dt UNSTEADY BOUNDARY-LAYER FLOW unsteady effect unsteady flow Unsteady Laminar Boundary unsteady term variable viscosity velocity profile viscous term wall heat Water Boundary Layers ди ду