- **Main CFD Forum**
(*http://www.cfd-online.com/Forums/main/*)

- - **Basic Fluid mechanics**
(*http://www.cfd-online.com/Forums/main/117411-basic-fluid-mechanics.html*)

Basic Fluid mechanicsHello everyone
I have very bad knowldege in fluid mechanics..Explain me about Newtanion fluid.I need the derivation for the topic called "CONSTITUTIVE EQUATIONS FOR NEWTONION FLUID"(or viscous fluid)..some 6 equations like towxx=2M(mu)(du/dx) similar for yy and zz include xy,yz and zx.. explain me pls |

Hi Sayee Chandrasekara Mouli,
Newtonian fluid means there is a linear relation between the stress and the strain-rate tensors (analogous to elasticity, where the stress is proportional to the strain). This is written (in tensor notation) asSik = -p * Iik +lambda * Emm * Iik + 2*mu * Eik where Sik is the stress, Eik is the strain-rate, p is the pressure, Iik is the identity tensor, mu is the viscosity, muv is the bulk viscosity (usually assumed 0, i.e., Stokesw assumption) and lambda=muv - 2/3* mu is similar to Lame constant in elasticity. The viscous stress, Tik, is defined as Tik = Sik + p * Iik The stain-rate is related to the velocity vector Ui through 2*Eik = Ui,k + Uk,i From these relations you can easily derive the relations you asked about. Rami |

All times are GMT -4. The time now is 17:18. |