CHEN 3005 Lecture 1: Lecture 1152014.pdf
25 Dec 2014
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= {convection of momentum}/{diffusion of momentum} = {inertia}/{viscosity} for a tube convected derivtive this t shouldn"t be there. Recall: substantial derivative of t for energy eqn thermal diffusivity [=] m2/s viscosity = conductivity of momentum k = conductivity of heat kinematic viscosity = diffusivity of momentum alpha = diffusivity of heat. {momentum diffusion}/ {thermal diffusion} plate = like sink for momentum can have thermal or velocity boundary layers. Chen transport page 3 when make dimensionless, can have one degree of freedom. Conevection time: jesse loi artifact both quantities have units of seconds but really want the rates, not how long it takesso we take inverse of time diffusion rate. Chen transport page 5 convection rate = vo/lo. Peclet # : heat transfer :: re : fluid transfer. If pe >> 1, then convection is more dominant (flow dominates) If pe << 1, then diffusion dominates (conduction dominates)
