M E 4210 Lecture Notes - Lecture 6: Sherwood Number, Surface Tension, Kinetic Energy

• School: Wayne State University
• Department: Mechanical Engineering
• Course: M E 4210
• Professor: Bashar S.Abdul Nour

Document Summary

Velocity (or momentum) boundary layer: [ 6. 1. 1] boundary layer (b. l. ) is defined to exist near the wall where the flow is sheared. The effect of viscosity causes the flow to be retarded and reach zero velocity adjacent to the wall; this is also called as the no slip boundary condition. B. l. thickness, (x), is defined as the distance normal to the wall where (cid:1873)/(cid:1847) (cid:3404)0. 99 . [ 6. 3. 1] transition from laminar b. l. to turbulent b. l. occurs at a critical reynolds number, re, which is defined as (cid:1844)(cid:1857)(cid:3051),(cid:3030)(cid:3045)(cid:3036)(cid:3047)(cid:3036)(cid:3030)(cid:3028)(cid:3039)(cid:3404)(cid:1847)(cid:3031)(cid:1850)(cid:3021)(cid:2029) [ 6. 1. 1] shear stress, , is directly proportional to the drag force; i. e. , ~ drag. The drag coefficient (or friction coefficient), which is a dimensionless parameter, is defined as. [ 6. 3. 1] the flow transitions from laminar to turbulent as the reynolds number, re, increases. There is a transition zone between the two in which the flow structure is not explicitly defined. Consider the difference between the laminar and turbulent b. ls.