Create a Free Molecular Heating simulation object

1. Choose Free Molecular Heating .

2. From the Type list, select an option that sets how the software determines which elements are illuminated for the free molecular heating.

3. If you selected Illuminate Selected Elements in the previous step, in the Top Side Illuminated Region and Bottom Side Illuminated Region groups, select the elements or polygon faces that are impacted by the free molecules.

4. In the Accommodation Coefficient box, enter the accommodation coefficient, α.The accommodation coefficient is used to compute the heat flux generated by the free low density gas molecules impacting the spacecraft surface. The value of α needs to be between 0 and 1.

5. From the Heat Flux Method list, select the heat flux computation method.

6. Depending on your choice in the previous step, do the following:If you selected Heat Flux, in the Heat Flux box, specify a constant or time-varying heat flux value.If you selected Velocity and Density:In the Velocity box, specify a constant or time-varying velocity value for the spacecraft.In the Density box, specify a constant or time-varying atmospheric density value.If you selected Density, in the Density box, specify a constant, time-varying, or altitude-varying atmospheric density value.For the Density heat flux computation method, because the software computes the velocity and density from the spacecraft’s orbital velocity and altitude, you must have an Orbit modeling object defined in your model.

7. From the Heat Flux Direction list, select an option to specify the direction of the free molecular heat flux.For the Heat Flux and Velocity and Density computation methods, you can select either Along Vector or Field for the Heat Flux Direction. For the Density computation method, you can only select From Orbit. In this case, the software determines the direction of the heat flux due to free molecular heating from the path that the spacecraft follows in the orbit. The direction opposes the velocity vector.

8. Depending on your choice in the previous step, do the following:If you selected Along Vector, specify the vector that represents the direction of the heat flux due to free molecular heating.If you selected Field, specify a table that defines the direction of the heat flux due to free molecular heating at specified times.

9. From the Monte Carlo Settings list, select a Monte Carlo Settings modeling object from the list or click Create Modeling Object to create a new modeling object.

10. Click OK.

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Create a Free Molecular Heating simulation object, Simcenter 3D 2021.1 Series

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