Numerical Simulation of Fluid Flows...
Transcript of Numerical Simulation of Fluid Flows...
Numerical Simulation of Fluid Flows
(BMEGEÁTAG26)
2015. 04. 23.
• András Tomor
• tomor [at] ara.bme.hu
• www.ara.bme.hu/~tomor/CFD/workbench
Main Rules: Whatever you do, do NOT use space and accents in file names! Work in: C:/Work/Neptun_code
Course leaders:
• László Nagy (nagy [at] ara.bme.hu)
•Balász Farkas (farkas [at] ara.bme.hu)
•András Tomor (tomor [at] ara.bme.hu)
•Bence Tóth (tothbence [at] ara.bme.hu)
• Tamás Benedek (benedek [at] ara.bme.hu)
– Transonic airfoil (2D, compressible)
1st And last chapter: Physical modeling and simulation
Run FLUENT
Drag and drop a FLUENT-item from Component Systems toolbox Double click on Setup and run FLUENT ! Choose the 2D simualtion option !
Download of base construction point set http://www.ara.bme.hu/oktatas/tantargy/NEPTUN/BMEGEATAG26/ENGLISH_course/2013-2014-II/ea_lecture/
Right click on basic construction points, select : „Hivatkozás mentése más néven…” , this means „Save target in different name…” (or „Save as”) in hungarian. Save the javascript for example in the: C:/Work/yourneptuncode/orifice/filename.js !Dont use space or any specific characters!
Download the mesh from http://www.ara.bme.hu/oktatas/tantargy/NEPTUN/BMEGEATAM05/2013-2014-II/ea-lecture/FLUENT/
Coose the 4th option from the top to get the mesh
Import Mesh
File/Import/Mesh
Density Based solver for high speed flows
Choose the Density Based Solver
Turbulence model
Turbulenc model: Spalart-Allmaras (This model was originally developed for airfoils)
Materials
Choose the ideal gas model for density calculations (By this the energy equations will be turned on automatically)
Pressure far field
Inelt boundary conditions : Pressure Far field (used specially for high speed flows to define the far field velocity) - Mach-szám: 0.8 - Y komponens: 0
Differencia schemes
Set Second order solvers for all the numerical schemes
Initialization
Solution initialization Standard intializition from: be (from the inlet boundary)
Run Calculation
Numer of iterations: 500
Results (Graphics and Animation in fluent)
Mach-number
Velocity Velocity vectors
Rersults
Static Temperature Total Temperature
Results
Static Pressure Total Pressure
Turbulent viscosity
Text User Interface (TUI)
Click on the Text User Interface, and press Enter, Current Menu going to appear In Fluent all the commands can be reached via TUI
Text User Interface
Type define/parameters into the command line – press enter (its basically the same as clicking on the Define menu what you can find in the main menu bar)
Text User Interface
If you press enter now you going to reach the parameters option Type enable-in-TUI – enter y (or yes) – enter By typing „q”-enter you can go back to the previous menupoint Type q twice (q q) – enter, like this you are back in the main menu
Text User Interface
Go back to define And choose the boundary-conditions option
Text User Interface To publish (set) a parameter for the y component of the velocity Choose pressure-farfield type boundary condition for the inlet (zone id/name [be]) that gonna be the default Keep pressing enter (keep the default settings) till you reach: Use Input Parameter for Y
Component of Flow Direction
Choose: y(es)
Name of parameter: tgalpha
Press enter
Calculation Activities
Now Use the Graphical User Interface!!! Set: Calculation Activities/ Automatically intialize and modify case: check Go to the edit menu: Originial settings/ check Nr. of iterations: 500
Output Parameters
Reports/Forces Forces, Direction: x=1 y=z=0, Zones: sz and ny (suction and pressure sides) Save Output Parameter, Create New … Name: fx (or something you prefer) Define the X component of the force as output parameter.
Output Parameters
Forces, Direction: y=1 x=z=0, Zones: sz and ny Save Output Parameter, Create New … Name: fy (or wahtever you prefere) Close FLUENT!
Runing Fluent in Parameter mode
Double click on parameters
Parametric running And try to cretae the following diagrams
0
2
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0
5000
10000
15000
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25000
30000
35000
40000
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50000
0 2 4 6 8 10 12 14 16 18
cl/c
d
F [N
]
alpha [°]
Fl Fd cl/cd
Parametric running
Choice of tgalpha is yours
Journal file
Every command can be written in a text file and with this text file we can make all of the commands with one click. An example: - Drag an other FLUENT on the workplace - Download the journal.jou file from the following page:
http://www.ara.bme.hu/~benedek/CFD/workbench/workbench_4th_practice/ - Copy it in the following place: C:\Work\neptun_code\myproject\myproject_files\dp0\FLU-1\Fluent - Start the Fluent Setup
Journal file
- Load in the previous mesh - Read the journal file:
/file/read/journal