# import transient fluent into transient structural simulation

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 January 30, 2022, 03:08 import transient fluent into transient structural simulation #1 New Member   power Join Date: Dec 2021 Posts: 6 Rep Power: 4 Hi all I did a transient simulation on a vertical axis wind turbine using fluent. Next, I imported the pressure at each time step to the transient structural software in order to analyze the stress and strain at each point of the blade. However the pressure parameter, which is imported to the transient structural software, contains negative magnitudes. I think that this negative pressure in fluent means that the pressure is below the operating pressure which is defined in fluent. When I am solving the stress and strain, the amount of stress in a place whose pressure is -200Pa is higher than the amount of stress in a place whose pressure is -5 Pa. Is that right ? I don't think so. In other words, -200 Pa pressure represents the relative value of pressure, and its absolute value is -200+101000=100800 Pa. Absolute value of pressure at -5 Pa spot can be calculated in the same way, which results in 100995 Pa, which is higher than 100800. Hence, the stress should be higher in a point with 100995 Pa than 100800 Pa point. But the results show the opposite. How should I turn the relative pressure values into absolute values without solving them again. Sorry for my poor English. Thanks a lot for your kind responses.

February 1, 2022, 03:41
#2
New Member

power
Join Date: Dec 2021
Posts: 6
Rep Power: 4
Quote:
 Originally Posted by power.pwoer123 Hi all I did a transient simulation on a vertical axis wind turbine using fluent. Next, I imported the pressure at each time step to the transient structural software in order to analyze the stress and strain at each point of the blade. However the pressure parameter, which is imported to the transient structural software, contains negative magnitudes. I think that this negative pressure in fluent means that the pressure is below the operating pressure which is defined in fluent. When I am solving the stress and strain, the amount of stress in a place whose pressure is -200Pa is higher than the amount of stress in a place whose pressure is -5 Pa. Is that right ? I don't think so. In other words, -200 Pa pressure represents the relative value of pressure, and its absolute value is -200+101000=100800 Pa. Absolute value of pressure at -5 Pa spot can be calculated in the same way, which results in 100995 Pa, which is higher than 100800. Hence, the stress should be higher in a point with 100995 Pa than 100800 Pa point. But the results show the opposite. How should I turn the relative pressure values into absolute values without solving them again. Sorry for my poor English. Thanks a lot for your kind responses.

I got the answer. When you click on the imported load part in Ansys mechanical, you will see the offset option. So, the offset pressure can be added.

But I have another problem. Is this right to consider absolute pressure in computing stress and strain of a body or the relative pressure should be considered to import in Ansys mechanical?

 Tags fluent, transient structure, unsteady fluent, vawt