Page History

{include: FLUENT Google Analytics}
{panel}
Author: John Singleton and Rajesh Bhaskaran

{color:#ff0000}{*}Problem Specification{*}{color}
[1. Pre-Analysis & Start-Up|FLUENT 12.1 -include: Unsteady Flow Past a Cylinder - Pre-Analysis & Start-Up]
[2. Geometry|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Geometry]
[3. Mesh|FLUENT 12.1 - Panel}

h1. Unsteady Flow Past a Cylinder - Mesh]
[4. Setup (Physics)|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Setup (Physics)]
[5. Solution|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Solution]
[6. Results|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Results]
[7. Verification and Validation|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Verification & Validation]
[Exercises|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Exercises]
{panel}

{note}Under Construction\!\!{note}


Created using ANSYS 13.0

h2. Problem Specification

\\  !prob_spec_v2.png!\\
\\
Consider the unsteady state case of a fluid flowing past a cylinder, as illustrated above. For this tutorial we will use a Reynolds Number of 120. In order to simplify the computation, the diameter of the cylinder is set to 1 m, the x component of the velocity is set to 1 m/s and the density of the fluid is set to 1 kg/m^3. Thus, the dynamic viscosity must be set to 8.333x10^-3 kg/m*s in order to obtain the desired Reynolds number.

Compared to the steady case, the unsteady case includes an additional time-derivative term in the Navier-Stokes equations:


{latex}
\begin{eqnarray}
\frac{\partial \vec{u}}{\partial t} + \rho (\vec{u}\cdot \triangledown)\vec{u} = -\triangledown p + \mu \triangledown^{2} \vec{u}
\end{eqnarray}
{latex}
The methods implemented by FLUENT to solve a time dependent system are very similar to those used in a steady-state case.  In this case, the domain and boundary conditions will be the same as the Steady Flow Past a Cylinder.  However, because this is a transient system, initial conditions at t=0 are required.  To solve the system, we need to input the desired time range and time step into FLUENT.  The program will then compute a solution for the first time step, iterating until convergence or a limit of iterations is reached, then will proceed to the next time step, "marching" through time until the end time is reached.
\\
\\
[*Go to Step 1: Pre-Analysis and Start-Up*|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Pre-Analysis & Start-Up]\\
\\
[See and rate the complete Learning Module|FLUENT 12.1 - Unsteady Flow Past a Cylinder - Problem Specification]\\
\\
[Go to all FLUENT Learning Modules|FLUENT Learning Modules]