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Merged
TobiKattmann merged 12 commits into from
Jul 31, 2021
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Unsteady CHT tutorial #26

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75726cf
Tutorial config files.
oleburghardt Feb 3, 2020
5a9d8a5
Tutorial config files (part 2).
oleburghardt Feb 3, 2020
ea756d9
First version for Unsteady CHT tutorial.
oleburghardt Feb 3, 2020
1d51df6
Include Unsteady CHT tutorial to index.
oleburghardt Feb 3, 2020
4fc3d94
Add youtube link for Unsteady CHT tutorial.
oleburghardt Feb 3, 2020
c171975
adding embedded youtube video
talbring Feb 3, 2020
2a6ab13
Minor corrections.
oleburghardt Feb 4, 2020
2f71137
Merge branch 'unsteady_cht_tutorial' of https://github.com/su2code/su…
oleburghardt Feb 4, 2020
271b1df
Merge remote-tracking branch 'origin/develop' into unsteady_cht_tutorial
TobiKattmann Mar 4, 2021
035a17a
Change links in unst cht, as files moved. Plus little fixes.
TobiKattmann Mar 4, 2021
ef60055
Replace some deprecated config options.
oleburghardt Mar 11, 2021
808f29f
Merge remote-tracking branch 'origin/develop' into unsteady_cht_tutorial
TobiKattmann Jul 31, 2021
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1 change: 1 addition & 0 deletions _data/tutorials.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@
- Static_FSI
- Dynamic_FSI_Python
- Static_CHT
- Inc_Heated_Cylinders_Unsteady

- title: Design Features
tutorials:
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12 changes: 8 additions & 4 deletions _tutorials/index.md
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Expand Up @@ -63,10 +63,11 @@ Simulation of external, viscous, incompressible flow around the NACA 0012 using
Simulation of internal, laminar, incompressible flow over a backward-facing step with an inlet velocity profile input from file.
* [Laminar Buoyancy-driven Cavity](/tutorials/Inc_Laminar_Cavity/)
Simulation of internal, laminar, incompressible flow in a differentially-heated cavity under the influence of gravity (classical natural convection case).
* [Streamwise Periodicity](/tutorials/Inc_Streamwise_Periodic/)
* [Streamwise Periodicity](/tutorials/Inc_Streamwise_Periodic/)
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@TobiKattmann TobiKattmann Mar 4, 2021

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These added spaces trigger line break here. Added for consistency

Simulation of internal, turbulent, incompressible flow in a unit cell of a 2D pin-fin heat exchanger.

#### Structural Mechanics

* [Linear Elasticity](/tutorials/Linear_Elasticity/)
Simulation of an elasticity problem with small deformations
* [Linear Dynamics](/tutorials/Linear_Dynamics/)
Expand All @@ -77,16 +78,19 @@ Simulation of a non-linear structural problem with large deformations
Simulation of a non-linear problem with multiple material definitions

#### Multiphysics

* [Static Fluid-Structure Interaction](/tutorials/Static_FSI/)
Non-linear structural mechanics coupled with incompressible Navier-Stokes flow
* [Dynamic Fluid-Structure Interaction with the Python wrapper](/tutorials/Dynamic_FSI_Python/)
* [Dynamic Fluid-Structure Interaction with the Python wrapper](/tutorials/Dynamic_FSI_Python/)
Linear Nastran-like model coupled with compressible unsteady RANS equations using the Python wrapper
* [Static Conjugate Heat Transfer](/tutorials/Static_CHT/)
* [Static Conjugate Heat Transfer](/tutorials/Static_CHT/)
Simulation of multiple heated cylinders in incompressible fluid flow.
* [Unsteady Conjugate Heat Transfer](/tutorials/Inc_Heated_Cylinders_Unsteady/)
Simulation of an unsteady coupled CHT problem incorporating multiple physical zones.

#### Shape Design Features

* [Unconstrained shape design of an transonic inviscid airfoil at a cte. AoA](/tutorials/Inviscid_2D_Unconstrained_NACA0012/)
* [Unconstrained shape design of an transonic inviscid airfoil at a cte. AoA](/tutorials/Inviscid_2D_Unconstrained_NACA0012/)
Get a basic introduction to the SU2 design capabilities by performing an optimal shape design of a 2D geometry (isolated airfoil) without constraints.
* [Constrained shape design of a transonic turbulent airfoil at a cte. C<sub>L</sub>](/tutorials/Turbulent_2D_Constrained_RAE2822/)
Perform an optimal shape design of a 2D geometry (isolated airfoil at turbulent regime) with flow and geometrical constraints.
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10 changes: 5 additions & 5 deletions _tutorials/multiphysics/steady_cht/Static_CHT.md
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---
title: Static Conjugate Heat Transfer (CHT)
permalink: /tutorials/Static_CHT
permalink: /tutorials/Static_CHT/
written_by: oleburghardt
for_version: 7.0.0
revised_by: oleburghardt
Expand Down Expand Up @@ -46,7 +46,7 @@ The correct interface temperature distribution has then to be found by the simul
This problem will solve for the incompressible flow over three cylinders as well as for the heat equation in all cylinders that are coupled by energy conservation across the interfaces.

The following flow conditions that are set to match the Reynolds number of 40. For hollow cylinders with outer diameters of 1m:
- Density (variable) = 0.00042 kg/m^3
- Density (variable) = 0.000210322 kg/m^3
- Farfield Velocity Magnitude = 3.40297 m/s
- Farfield Flow Direction, unit vector (x,y,z) = (1.0, 0.0, 0.0)
- Farfield Temperature = 288.15 K
Expand Down Expand Up @@ -127,13 +127,13 @@ MARKER_ISOTHERMAL= ( core1, 350.0 )
The solid's material properties are chosen as follows.
```
% Solid density (kg/m^3)
SOLID_DENSITY= 0.00021
MATERIAL_DENSITY= 0.00021
%
% Solid specific heat (J/kg*K)
SPECIFIC_HEAT_CP_SOLID = 1004.703
SPECIFIC_HEAT_CP = 1004.703
%
% Solid thermal conductivity (W/m*K)
THERMAL_CONDUCTIVITY_SOLID= 0.1028
KT_CONSTANT= 0.1028
```

### Running SU2
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88 changes: 88 additions & 0 deletions _tutorials/multiphysics/unsteady_cht/Inc_Heated_Cylinders_Unsteady.md
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---
title: Unsteady Conjugate Heat Transfer
permalink: /tutorials/Inc_Heated_Cylinders_Unsteady/
written_by: oleburghardt
for_version: 7.1.0
revised_by: TobiKattmann
revision_date: 2021-03-04
revised_version: 7.1.1
solver: INC_NAVIER_STOKES, HEAT_EQUATION
requires: SU2_CFD
complexity: advanced
follows: Static_CHT
userguide: Multizone
---

<br>
<iframe width="560" height="315" src="https://www.youtube.com/embed/MqN8GalSyzk" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

## Goals

This tutorial is a follow-up on the [heated cylinders with conjugate heat transfer tutorial](/tutorials/Inc_Heated_Cylinders/) where a steady CHT solution was computed for a problem involving multiple physical zones.
The following capabilities of SU2 will be showcased in this tutorial:

- Time domain and time-marching config file options (plus related ones) for unsteady simulations
- Use of time iterations, outer and inner iterations
- Paraview multiblock output

The intent of this tutorial is to demonstrate how a steady CHT simulation can be turned into an unsteady one.

## Resources

The resources for this tutorial can be found in the [Inc_Heated_Cylinders_Unsteady](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht) directory in the [tutorial repository](https://github.com/su2code/Tutorials). You will need the configuration files for all physical zones ([flow_cylinder.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/flow_cylinder.cfg), [solid_cylinder1.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/solid_cylinder1.cfg), [solid_cylinder2.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/solid_cylinder2.cfg), [solid_cylinder3.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/solid_cylinder3.cfg)), the cofiguration file to invoke a multiphysics simulation run ([cht_2d_3cylinders.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/cht_2d_3cylinders.cfg)) and the mesh file ([mesh_cht_3cyl.su2](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/mesh_cht_3cyl.su2)).

## Tutorial

The following tutorial will walk you through the steps required when solving for an unsteady coupled CHT solution. It is assumed you have already obtained and compiled the SU2_CFD code for a serial computation. If you have yet to complete these requirements, please see the [Download](/docs/Download/) and [Installation](/docs/Installation/) pages and that make sure you have completed the [heated cylinders with conjugate heat transfer tutorial](/tutorials/Inc_Heated_Cylinders/).

### Background

For unsteady flows around walls that are transferring heat from an adjacent (solid) zone, the coupling of temperature and heat flux distributions has to be resolved for each and every time step. Both will vary over time as they depend on the current flow field.

### Problem Setup

The problem setup is the same as in the [heated cylinders with conjugate heat transfer tutorial](/tutorials/Inc_Heated_Cylinders/) except for the density. It is increased in all zones by a factor of 100 so that for the flow we obtain a Reynolds number of 4000 which will make it unsteady. Thus we set
```
INC_DENSITY_INIT= 0.0210322
```
in [flow_cylinder.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/flow_cylinder.cfg) and

```
MATERIAL_DENSITY= 0.0210322
```
in [solid_cylinder1.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/solid_cylinder1.cfg), [solid_cylinder2.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/solid_cylinder2.cfg) and [solid_cylinder3.cfg](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/solid_cylinder3.cfg)

For simplicity we leave all other parameters unchanged.

### Mesh Description

The [mesh](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/mesh_cht_3cyl.su2) is the same as in the [heated cylinders with conjugate heat transfer tutorial](/tutorials/Inc_Heated_Cylinders/).

### Configuration File Options

An unsteady simulation is set up by enabling the time domain and choosing a time marching algorithm in the [master config file](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/cht_2d_3cylinders.cfg):

```
TIME_DOMAIN = YES
%
%
TIME_MARCHING= DUAL_TIME_STEPPING-2ND_ORDER
```

The time marching parameters have to match the flow physics that should be resolved. For a given inlet velocity of 3.40297 m/s at Re = 4000, the Strouhal number estimation for the most upstream cylinder is Sr = 0.21. This gives a frequency of f = Sr*v = 0.71Hz for the vortex shedding so that a time step of 0.05s is chosen in the [master config file](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/cht_2d_3cylinders.cfg):

```
TIME_STEP= 0.05
```

In order to sufficiently resolve the coupling in each time step, we set the number of outer iterations to 200 in the [master config file](https://github.com/su2code/Tutorials/tree/master/multiphysics/unsteady_cht/cht_2d_3cylinders.cfg):

```
OUTER_ITER = 200
```

The number of inner (zone-internal) iterations is set to 1 by default. We do not have to touch any of the zone-specific config files for unsteady options.

### Running SU2

One time iteration will run rather quick and it is up to the user for how long the simulation should run or, equivalently, which physical time span should be covered. In the video above, 1000 time steps had been computed to generate a 50s realtime video. See the [heated cylinders with conjugate heat transfer tutorial](/tutorials/Inc_Heated_Cylinders/) how to execute SU2_CFD.