You use Estimated Variation to indicate the expected difference between the maximum and minimum temperature in the model during the analysis. You can enter a value or select Auto. If you select Auto, the engine estimates a value from the applied heat loads and convection conditions.

If you enter a value, it must correspond to the temperature variation that you expect your model to experience during the analysis. This value, which must be a positive number, works with the value you set in the Accuracy field to control the accuracy of the time integration.

The estimated temperature variation you enter need only be the correct order of magnitude to ensure that Creo Simulate controls time integration errors properly and efficiently. If you enter a value for estimated temperature variation that is too small, the engine may warn that it took too many time steps. However, if at any point in the analysis the actual temperature variation exceeds your specified value, or the value estimated by the engine from the applied heat loads, the engine proceeds with the larger value, computed as a result of the time integration.

If the engine warns that the estimated temperature variation was too large, the solution may still be sufficiently accurate because of the control of errors in energy norm. You can verify this by re-running the analysis a second time with the Estimated Variation equal to the value of temperature variation reported by the engine in the original analysis.

Alternatively, you can use the quick check analysis to compute the temperature variation in the model and enter that value for Estimated Variation before running a transient thermal analysis with single-pass adaptive convergence.