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How to deal with non-convergence while simulating compressible flow inside an aerospike nozzle?

    • jaiswal1706
      Subscriber

      Problems I am facing:

      1. Reverse flow at the outlet (I tried extending the domain, but to no avail.)

      2. Maximum temperature/ pressure limited in....

      3. Solution not converging, particularly the residual for continuity. Other residuals also take a lot of iterations for converging


      Kindly find the details of the set-up here:

      1. Steady State, Density-based, Axis-symmetric

      2. Spalart Allmaras Turbulence Model with energy eqn on

      3. Air modeled as ideal gas with Sutherland model of viscosity

      4. BCs: (i) Pressure inlet, Gauge Total Pressure = (NPR*101325 - 101325) ; Supersonic/ initial Gauge Pressure = 5 Pa less than the total pressure; Total Temperature = 300 K.

      (ii) Pressure outlet, Gauge Pressure = 0 Pa, Total Temperature = 300 K

      (iii) Temperature of 300 K applied at walls

      (iv) Operating Pressure = 101325 Pa



      Details regarding mesh:

      Structured mesh with 2,52,958 cells.

      Avg. element quality = 0.79571, Min. element quality = 0.28747

      Avg. skewness = 1.2058e-002, Max skewness = 0.35188

      Avg. aspect ratio = 2.0994, Max aspect ratio = 6.7975

      Avg. orthogonality = 0.99705, Min orthogonality = 0.85175


      Kindly help me on this. I am also attaching the pictures of domain and mesh being used for the simulation.

    • Rob
      Forum Moderator
      Please add some images of the results. Note, the jump in cell size won't help but the problem may lie in the mesh resolution or initial conditions.
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