Hello everyone,
I hope this message finds you well. I am a beginner in using ASPECT, and I am currently working with the viscoplastic model and aiming to create a model in which there is only dislocation creep in the crust (using composite viscosity by setting the diffusion creep extremely large, ~1e50). For the initial temperature field setup, I am using .txt files. The relative viscosity range I am employing is from 1e-2 to 1e4 (with a reference viscosity of 1e21, within a range of 1e19 to 1e25). I’ve also set the “minimum strain rate” and “initial strain rate” to 1e-21.
However, I have encountered a few issues that I would greatly appreciate your insights on:
- After setting dislocation creep, I noticed that the dislocation viscosity output from ASPECT appears inconsistent with the viscosity calculations made using my Python script. This discrepancy occurs despite using the same rheological parameters and inputting the temperature, pressure, and strain rate obtained from the .pvtu file. In the figure I have created, at Step 0, near the bottom of the crust, I am trying to achieve two nearly coincident curves (shown in blue and orange), but there is still a noticeable gap. When I use the Step 1 results from ASPECT for input, they seem to return to normal. I don’t know why this happens, and I wonder if it relates to how I have set up the initial temperature field.
- To debug composite viscosity, I compared my results with those from Underworld, using UW’s output for temperature and pressure along with strain rate in my Python calculations. This indicated that my viscosity parameters are indeed correct, as the UW output viscosity follows the Python script computed composite viscosity in both the crust and mantle depths. However, even with the same viscosity parameters and temperature(input T file is output from the UW model), I am experiencing differences in strain rates that seem to cause gaps in the viscosity values between both models. While I have tried to keep the parameters the same on both sides, there may still be differences in setting and in the result. However, from Step 1 onward, it appears that both outputs begin to align more closely. Could this viscosity difference problem be connected to the initial temperature field setup or the order in which the physical fields are resolved?
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I considered leaving points with specific x coordinates, like 0.5 (all pictures above are chosen at the middle of the model), then sorting them by depth to obtain curves reflecting field changes with depth. However, when I followed the method outlined in (Loading VTK data into Python) to load the .pvtu files into Python, I encountered many repeated (x, y) pairs, resulted in multiple values appearing at the same depth in the above figures. How should I deal with these points and process the .pvtu files more appropriately?
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Additionally, I noticed that the viscosity field at my model’s top oscillates starting from Step 1. I would be very grateful if you could advise me on which parameters I should pay special attention to to avoid such oscillations.
T_input.txt (5.1 MB)
testall_field.prm (5.1 KB)
Thank you very much in advance for your assistance! I sincerely apologize for the number of questions and truly appreciate your time and expertise.
Best regards,
Junru