Sifu: Use this defence if someone attacks you with a knife like this ...
Student: But what if it was like this instead ...
Sifu: Well we were talking about a certain situation, but in your instance you could ...
Student: What if he had two knives?
Sifu: ...
Student: What if one of the knives was a bunch of flowers and the person had really bad hayfever?
Thursday, 10 April 2014
Tuesday, 25 March 2014
openFoam wisdom
Specify velocity AND pressure at a boundary and expect continuity errors. Set zero gradient (not non-zero gradient) and velocity.
------------------
Calculate initial k and epsilon values with this script:
#!/bin/sh
echo ' ==========================================='
echo ' give me Uref, Turbulent Intensity and L'
echo ' I will give you TKE and epsilon for inlet'
echo ' ==========================================='
###
Uref=$1
ti=$2
L=$3
tke=$(echo "scale=4;1.5 *($Uref * $ti)^2"|bc -l )
epsilon=$(echo "scale=4;0.09^(3/4)*$tke^(3/2)/$L"|bc -l)
echo 'tke =' $tke
echo 'eps =' $epsilon
(matejfor, http://www.cfd-online.com/Forums/openfoam-solving/57839-simplefoam-time-step-continuity-errors.html)
------------------
------------------
Calculate initial k and epsilon values with this script:
#!/bin/sh
echo ' ==========================================='
echo ' give me Uref, Turbulent Intensity and L'
echo ' I will give you TKE and epsilon for inlet'
echo ' ==========================================='
###
Uref=$1
ti=$2
L=$3
tke=$(echo "scale=4;1.5 *($Uref * $ti)^2"|bc -l )
epsilon=$(echo "scale=4;0.09^(3/4)*$tke^(3/2)/$L"|bc -l)
echo 'tke =' $tke
echo 'eps =' $epsilon
(matejfor, http://www.cfd-online.com/Forums/openfoam-solving/57839-simplefoam-time-step-continuity-errors.html)
------------------
Friday, 14 March 2014
Wednesday, 5 March 2014
Monday, 10 February 2014
Friday, 7 February 2014
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