1. CE 1501 Flow Over Immersed Bodies Reading: Munson, et al., Chapter 9

2. CE 1502 Introduction Internal vs. external flows Applications –air flow over aircraft and surface vehicles (aerodynamics) –wind flow around buildings –water flow about marine vehicles –water flow around marine structures

3. CE 1503 Flow Characteristics Analysis usually treats fluid flowing past stationary body with upstream velocity U that is uniform and steady. Flow classification –Two-dimensional: one dimension is “infinitely” long –Axisymmetric: formed by rotation of a cross-sectional area –Three-dimensional: may not have an axis of symmetry

4. CE 1504 Flow Characteristics Lift (vertical force) and drag (horizontal force) Both are due to combination of fluid pressure and shear stresses acting on the surface of a body Drag coefficient: Lift coefficient:

5. CE 1505 Flow Characteristics Reynolds number effects –Viscous forces –Inertia forces Wake region Boundary layer Separation

6. CE 1506 The Boundary Layer Boundary layer thickness (  ) Displacement thickness (  *) Momentum thickness (  ) Laminar boundary layer –Prandtl-Blausius solution -Smooth, flat plate -Transition boundary layer -Turbulent boundary layer

7. CE 1507 Drag Drag coefficient Dimensional analysis yields Total drag = Friction drag + Pressure (form) drag

8. CE 1508 Drag Effects –Shape –Reynolds number –Mach number (compressibility) –Froude number –Surface roughness

9. CE 1509 Lift Lift coefficient Dimensional analysis yields Lift only occurs when there exists asymmetry in the flow field around an object and is largely due to pressure forces

10. CE 15010 Lift Effects –Shape and “angle of attack” –Reynolds number –Mach number (compressibility) –Froude number –Surface roughness