# How to plot velocity Vs time graph at a point in a flow using starccm+

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 November 9, 2012, 02:58 How to plot velocity Vs time graph at a point in a flow using starccm+ #1 New Member   Taryk Join Date: Nov 2012 Posts: 9 Rep Power: 11 I m trying to plot a graph of velocity magnitude vs time at a point in a turbulent flow over a flat plate using point probe but i m unable to get a graph. Can anyone help me in sorting out this problem. Thanks TQIM

 November 9, 2012, 16:43 #2 Senior Member     Sergei Join Date: Dec 2009 Posts: 258 Rep Power: 18 Create an expression report. Set your point derived part as an input part for it. Define a report expression as sqrt(\$\$Velocity[0]^2+\$\$Velocity[1]^2+\$\$Velocity[2]^2). Create a monitor and a plot from your report. Go to the monitor properties and switch the trigger from 'every iteration' to 'every time step'.

November 12, 2012, 09:19
#3
Senior Member

Ryne Whitehill
Join Date: Aug 2009
Posts: 312
Rep Power: 16
Quote:
 Originally Posted by Zeppo Create an expression report. Set your point derived part as an input part for it. Define a report expression as sqrt(\$\$Velocity[0]^2+\$\$Velocity[1]^2+\$\$Velocity[2]^2). Create a monitor and a plot from your report. Go to the monitor properties and switch the trigger from 'every iteration' to 'every time step'.

You could probably just use a sum report and only include that point.

Also, I think \$\$Velocity.mag() would be easier than doing the full equation.

 November 15, 2012, 20:26 #4 Senior Member   Join Date: Oct 2009 Location: Germany Posts: 637 Rep Power: 19 Again, rwryne is right. There is a field function syntax to get the velocity magnitude, but isn't it mag(\$\$Velocity)? At least that's what the user guide tells on page 4784. Anyway, on an expression report, you can't choose any input parts, so it needs to be a sum, minimum or maximum report. All other reports don't make much sense. __________________ We do three types of jobs here: GOOD, FAST AND CHEAP You may choose any two!

 November 19, 2012, 02:18 #5 New Member   Taryk Join Date: Nov 2012 Posts: 9 Rep Power: 11 Thanks for your reply...I tried with the expression given by you but its giving syntax error. Could you please tell me how to rectify this error.

 November 19, 2012, 02:20 #6 New Member   Taryk Join Date: Nov 2012 Posts: 9 Rep Power: 11 Thanks Ryne for your reply but I m getting syntax error when I used the expression given by you. Could you please tell me how to rectify this error.

November 19, 2012, 11:51
#7
Senior Member

Reza
Join Date: Mar 2009
Location: Appleton, WI
Posts: 116
Rep Power: 14
Can you post the error message? I think the following post gives the correct syntax

Quote:
 Originally Posted by abdul099 Again, rwryne is right. There is a field function syntax to get the velocity magnitude, but isn't it mag(\$\$Velocity)? At least that's what the user guide tells on page 4784. Anyway, on an expression report, you can't choose any input parts, so it needs to be a sum, minimum or maximum report. All other reports don't make much sense.