Newtonian fluid¶
Module: fluid
Category: materialprop
Type string: "Newtonian fluid"
Parameters¶
| Name | Description | Default | Units |
|---|---|---|---|
kappa |
bulk viscosity | 0 | [P.t] |
mu |
shear viscosity | 0 | [P.t] |
Description¶
The material type for a Newtonian fluid is Newtonian fluid.
The viscous shear stress for this material model is
\[
\boldsymbol{\tau}=\left(\kappa-\frac{2}{3}\mu\right)\left(tr\mathbf{D}\right)\mathbf{I}+2\mu\mathbf{D}
\]
Stokes' condition is a constitutive assumption that sets \(tr\boldsymbol{\tau}=0\), implying that \(\kappa=0\). This assumption is only valid for some fluids (e.g., monoatomic gas 1). Users may use or ignore this assumption by selecting an appropriate value for \(\kappa\).
Example:
<viscous type="Newtonian fluid">
<mu>0.001</mu>
<kappa>0</kappa>
</viscous>
-
Panton, Ronald L, Incompressible flow (John Wiley & Sons, 2006). ↩