# FlowType

## 1 Name

flowType - Calculates and writes the flowType of velocity field U.

## 2 Synopsis

flowType [OPTIONS]

## 3 Description

Calculates and writes the flowType of velocity field U.

The flow type parameter is obtained according to the following equation: $\lambda = \frac {\| D \| - \| \Omega \|}{\| D \| + \| \Omega \|}$

-1 = rotational flow
0 = simple shear flow
1 = planar extensional flow

-noZero

Exclude the 0 directory from the times list

-time RANGES

Select time steps. RANGES follows the time selection rules

-latestTime

Apply only on the latest time available

-constant

Include the constant directory in the times list

-parallel

Run the utility in parallel

-roots "(DIR1 [...DIRN])"

Directories through which the data are distributed

-region NAME

Specify a mesh region by its NAME

-case DIR

Execute the command on the case directory DIR. If not provided, use the current directory

-noFlow

suppress creating flow models (execFlowFunctionObjects only)

-noFunctionObjects

Skip the execution of the functionObjects

-help

Display the help and exit

The -noWrite option has no meaning.

## 4 Background

The formula used is: $\lambda = \frac {\| D \| - \| \Omega \|}{\| D \| + \| \Omega \|}$

where

D = symm(grad(U)) = $\frac{1}{2} \left( \frac{\partial U_i}{\partial x_j} + \frac{\partial U_j}{\partial x_i} \right)$ $\Omega$ = skew(grad(U)) = $\frac{1}{2} \left( \frac{\partial U_i}{\partial x_j} - \frac{\partial U_j}{\partial x_i} \right)$