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Drag plot

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Radon_Autodesk
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Drag plot

 Hello, 

In the Drag Plot, what are the units of time?

Even after I run a simulation for hours the values on the screen are very small, for example a simulation of near 12 hours gave me Time: 00:00:00.08. The Cd had been constant for several hours at 0.87, the simulation still in "Transient"

Could you please help interpreting this?

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hartogj
in reply to: Radon_Autodesk

Flow Design is a transient solver which simulates behavior of flow over time in the wind tunnel. It calculates the behavior at discrete intervals (timesteps) and proceeds from one to the next. The "time" reported in the drag plot is the cumulative amount of simulated time for the simulation. Results tend to approximate steady state conditions after you've covered at least 1 average fluid residence time (tunnel length/wind speed). You'll see the status indicator switch from "Transient" to "Stabilized" when you get beyond this point in time.

 

The amount of time covered in each step or iteration is dependent upon the model and automatically determined by the solver based on the physics of your setup. You'll notice that some setup conditions (for example, fast flows through short wind tunnels) will cause the solver to use a very small timestep to make sure the behavior is captured.



Jon den Hartog

Product Manager

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