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How to define a motion to simulate the oscillating airfoil

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Old   April 8, 2014, 17:47
Smile How to define a motion to simulate the oscillating airfoil
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I want to simulate the oscillating airfoil by using dynamic mesh in time domain. How can I define the motion?
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Old   April 8, 2014, 22:27
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Create a rotating region inside your exterior region. Then create a motion for the rotating region under tools>motion. Define a function (probably some kind of sine wave) for that motion.
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Old   April 8, 2014, 22:51
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Thank you for reply. How to define a sine wave motion in star com? I can not find the option of UFD. There are only settings for rotation axis, anglar velocity...etc




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Create a rotating region inside your exterior region. Then create a motion for the rotating region under tools>motion. Define a function (probably some kind of sine wave) for that motion.
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Old   April 9, 2014, 03:36
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may be you can create a transition motion,and create a function to control the motion.
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Old   April 9, 2014, 12:16
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Just type in a function in the field for the rotation rate.
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Old   April 9, 2014, 13:22
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Thank you so much. Can you give me a sample of function, such as a motion of frequency 10Hz and amplitude -5 to 5 degrees. Or can I find some useful information from the UserGuide? I can not find it so far...

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Just type in a function in the field for the rotation rate.
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Old   April 9, 2014, 13:34
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Look for the section using tools> using field functions
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Old   April 9, 2014, 16:22
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I have defined a new field function which named "Motion", the expression is 0.5*sin(2*3.14*$Time). Then I type "$Motion" in rotation rate and got the warning below:

"Error: Unable to compile field function: Motion (Motion)
Cannot resolve function ${time}: "time" not defined."

what does that mean?


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Look for the section using tools> using field functions
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Old   April 9, 2014, 18:14
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This error is likely because your physics continuum is not set to be unsteady. The function $Time does not exist for steady cases.

Note your field function must return radians/s. Originally you wanted it to turn through some degree sweep - ensure (a) that you are using radians and (b) you differentiate your function so it is a rotation rate.
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Old   April 9, 2014, 18:48
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i chose the implicit unsteady solver. The new field function including $Time can be created normally. The error showed up when I defined the rotation rate.






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This error is likely because your physics continuum is not set to be unsteady. The function $Time does not exist for steady cases.

Note your field function must return radians/s. Originally you wanted it to turn through some degree sweep - ensure (a) that you are using radians and (b) you differentiate your function so it is a rotation rate.
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Old   April 9, 2014, 20:02
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Be sure you are using a capital T as well. It worked for me when I tried it.
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Old   April 9, 2014, 22:34
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Yes, I used a capital T. Do I need a $ and rad/s in rotation rate? Or just the name of field function?


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Be sure you are using a capital T as well. It worked for me when I tried it.
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Old   April 9, 2014, 22:49
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No, just the $fieldFunctionName.

Go through your field function list and ensure that Time is one of them. If it is not one of your physics continua is set incorrectly.
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Old   April 9, 2014, 23:02
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HI,how should i creat the rotational region?
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Old   April 9, 2014, 23:55
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Quote:
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HI,how should i creat the rotational region?
datouguaiguai, that is not enough information to be useful. If you're having a problem, please create your own thread.
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Old   April 10, 2014, 14:56
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It works now. Thank you so much for your help.

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No, just the $fieldFunctionName.

Go through your field function list and ensure that Time is one of them. If it is not one of your physics continua is set incorrectly.
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Old   August 20, 2014, 17:55
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Shelley,

Is there a way to make an animation of an airfoil oscillating with the varying velocity distribution shown?
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