AME 60634 Int. Heat Trans. D. B. Go Fluid Dynamics: Boundary Layers Given equivalent boundary conditions, the solutions take the same form Analogous Equations • if two normalized (dimensionless) equations take the same form the equations are analogous The momentum and energy boundary layer equations are analogous if there is a negligible pressure gradient (dp*/dx* ~ 0) and the Pr ~ 1 Reynolds Analogy
Fluid Dynamics: Boundary Layers. Analogous Equations if two normalized (dimensionless) equations take the same form the equations are analogou s. Reynolds Analogy. - PowerPoint PPT Presentation
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AME 60634 Int. Heat Trans.
D. B. Go
Fluid Dynamics: Boundary Layers
Given equivalent boundary conditions, the solutions take the same form
Analogous Equations• if two normalized (dimensionless) equations take the same form the
equations are analogous
The momentum and energy boundary layer equations are analogous if there is a negligible pressure gradient (dp*/dx* ~ 0) and the Pr ~ 1
Reynolds Analogy
AME 60634 Int. Heat Trans.
D. B. Go
Fluid Dynamics: Boundary Layers
The Reynolds Analogy is defined as (when Pr =1)
The Reynolds Analogy implies that under certain conditions (no pressure gradient, Pr = 1) if the velocity parameters are known than the heat transfer parameters can be determined (and vice versa)
Colburn j factor
laminar flows: valid for dp*/dx* ~ 0turbulent flows: generally valid without restriction on dp*/dx*