Ch6_bw_PDF - Introduction to Convection Flow and Thermal Considerations Chapter Six Sections 6.1 6.3 and 6.6 Sections 6.4 and 6.5(only concepts

Ch6_bw_PDF - Introduction to Convection Flow and Thermal...

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1 Introduction to Convection: Flow and Thermal Considerations Chapter Six Sections 6.1- 6.3 and 6.6 Sections 6.4 and 6.5 (only concepts + equations 6.47 to 6.50) We will not cover mass transfer in this chapter and in this course 1 2
2 Internal versus External Flow 3 Boundary Layer Features Boundary Layers: Physical Features Velocity Boundary Layer A consequence of viscous effects associated with relative motion between a fluid and a surface. A region of the flow characterized by shear stresses and velocity gradients. A region between the surface and the free stream whose thickness increases in the flow direction. 0.99 u y u Why does increase in the flow direction? Manifested by a surface shear stress that provides a drag force, . s D F 0 s y u y s D s s A F dA How does vary in the flow direction? Why? s 4 The frictional drag on the plate may be determined from the local friction coefficient, given as 2 2 U s f C