Prandtl Number

04/12/18

“How can we quantify the ratio between momentum and thermal diffusivity?”

 

For fluids flowing over an object’s surface, momentum and heat will be transferred, oftentimes at different rates. How quickly one changes with respect to the other will completely affect its properties. As a result, engineers have devised something known as the Prandtl Number, which compares the diffusivity of momentum and heat as a ratio, symbolized as pr = c_p*Mu/k with C_p being the specific heat capacity of a gas at constant pressure, Mu being the dynamic viscosity and k the thermal conductivity.