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"# Time-Accurate Rotor with Thrust-Convergence Stopping Criterion\n",
"\n",
"This notebook demonstrates how to configure a **run control stopping criterion** for a time-accurate rotor simulation. The criterion monitors the mean thrust (CFz) averaged over the last two rotor revolutions and halts the simulation automatically once the mean has converged - avoiding manual step-count tuning.\n",
"\n",
"The geometry is the **DTU 10MW reference wind turbine** (blade radius R ≈ 89 m). The setup uses a time-accurate sliding-interface approach, so the physical time step size and maximum number of revolutions are derived from the single parameter `dt_deg`.\n",
"\n",
"Key features covered:\n",
"- Project creation from a local CAD geometry file (beta mesher)\n",
"- Time-accurate unsteady simulation with a sliding rotating zone\n",
"- `ForceOutput` with `MovingStatistic` computing a rolling mean over the last two revolutions\n",
"- `RunControl` with a `StoppingCriterion` tied to the rolling-mean thrust output\n",
"\n",
"**Note:** The settings in this example are by no means a validation setup; they are crafted to showcase the capabilities of Flow360 and we have intentionally reduced node count and example FC cost. For rigorous validation, modify the settings as needed."
],
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"source": [
"## 1. Load a Project\n",
"\n",
"Load the Flow360 client and create a new project from the DTU 10MW EGADS geometry file (length unit: metres)."
],
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"Output()"
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"text/html": [
"[09:58:38] INFO : Geometry successfully submitted: \n",
" type = Geometry \n",
" name = DTU Wind Turbine stopping-criterion tutorial \n",
" id = geo-f3c47111-91b5-44c0-afd5-a7c3d811fb73 \n",
" status = uploaded \n",
" project id = prj-efdd1dbc-c9e4-4d01-895a-cc034e4caae6 \n",
" \n",
" INFO : Waiting for geometry to be processed. \n",
"[10:00:03] INFO : using: SI unit system for unit inference. \n",
"[10:00:19] INFO : using: SI unit system for unit inference. \n",
"[10:00:30] INFO : Selecting beta/in-house mesher for possible meshing tasks. \n",
"[10:00:32] INFO : Successfully submitted: \n",
" type = Case \n",
" name = Rotor stopping-criterion tutorial \n",
" id = case-74362a34-2da8-4103-9e44-2d107f4a882b \n",
" status = pending \n",
" project id = prj-efdd1dbc-c9e4-4d01-895a-cc034e4caae6 \n",
" \n",
"[10:40:21] INFO : Saved to /tmp/tmpmhddaw8j/ 8cf86ebe-6df6-4bd7-9bd5-bc741362c849.csv \n",
"[10:40:22] INFO : Saved to /tmp/tmpmhddaw8j/ 00a155c2-d9ff-4dc0-b2c1-836e26a8cae0.csv \n",
"[10:40:24] INFO : Saved to /tmp/tmpmhddaw8j/ 78a71559-9f75-4229-abf2-47c1002d63a5.csv \n",
""
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{
"name": "stdout",
"output_type": "stream",
"text": [
"Simulation stopped at physical step 606 (10.1 revolutions)\n"
]
}
],
"source": [
"case.wait()\n",
"\n",
"# Reference quantities for dimensionalization\n",
"density = case.params.operating_condition.thermal_state.density\n",
"U_ref = case.params.operating_condition.velocity_magnitude\n",
"A_ref = case.params.reference_geometry.area\n",
"q = 0.5 * float(density) * float(U_ref) ** 2 * float(A_ref)\n",
"\n",
"# Thrust monitors\n",
"thrust_monitor_mean = case.results.custom_forces[\"thrust_monitor_moving_statistic\"].as_dataframe()\n",
"thrust_monitor_mean[\"Thrust_mean [N]\"] = thrust_monitor_mean[\"totalCFz_mean\"]\n",
"thrust_monitor_mean_step = thrust_monitor_mean[\"end_index\"]\n",
"thrust_monitor = case.results.custom_forces[\"thrust_monitor\"].as_dataframe()\n",
"thrust_monitor[\"Thrust [N]\"] = thrust_monitor[\"totalCFz\"]\n",
"thrust_monitor_step = thrust_monitor[\"physical_step\"]\n",
"\n",
"# --- Plot ---\n",
"fig, axes = plt.subplots(2, 1, figsize=(10, 8), sharex=False)\n",
"\n",
"axes[0].plot(\n",
" thrust_monitor[\"physical_step\"],\n",
" thrust_monitor[\"Thrust [N]\"],\n",
" color=\"steelblue\",\n",
" alpha=0.5,\n",
" linewidth=0.8,\n",
" label=\"Instantaneous\",\n",
")\n",
"axes[0].plot(\n",
" thrust_monitor_mean[\"end_index\"],\n",
" thrust_monitor_mean[\"Thrust_mean [N]\"],\n",
" color=\"navy\",\n",
" linewidth=2,\n",
" label=f\"{revs_for_mean}-rev rolling mean\",\n",
")\n",
"axes[0].set_ylabel(\"Thrust [N]\")\n",
"axes[0].legend()\n",
"axes[0].grid(True, alpha=0.3)\n",
"axes[0].set_title(\"Thrust convergence\")\n",
"\n",
"# Residuals: include pseudo steps, show only last revolution (via x limit)\n",
"final_step = thrust_monitor[\"physical_step\"].iloc[-1]\n",
"non_linear = case.results.nonlinear_residuals.as_dataframe()\n",
"nl = non_linear.copy()\n",
"max_ps = nl[\"pseudo_step\"].max() + 1\n",
"nl[\"step_with_pseudo\"] = nl[\"physical_step\"] + nl[\"pseudo_step\"] / max_ps\n",
"for col in [\"0_cont\", \"1_momx\", \"2_momy\", \"3_momz\", \"4_energ\", \"5_nuHat\"]:\n",
" if col in nl.columns:\n",
" axes[1].semilogy(nl[\"step_with_pseudo\"], nl[col], label=col, alpha=0.7)\n",
"axes[1].set_xlim(final_step - steps_per_rev + 1, final_step + 1)\n",
"axes[1].set_xlabel(\"Physical step (with pseudo steps)\")\n",
"axes[1].set_ylabel(\"Nonlinear residual\")\n",
"axes[1].legend(fontsize=8)\n",
"axes[1].grid(True, alpha=0.3)\n",
"\n",
"plt.tight_layout()\n",
"plt.show()\n",
"\n",
"print(\n",
" f\"Simulation stopped at physical step {final_step} \"\n",
" f\"({final_step / steps_per_rev:.1f} revolutions)\"\n",
")"
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