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"# Rotating Zone Cutting Through the Geometry\n",
"\n",
"A tractor propeller is usually mounted on a spinner that blends into a stationary nacelle or motor pod. To simulate it with a rotating zone, the zone has to end somewhere along that body, and the CAD normally needs a split line exactly where the zone boundary crosses it. With **GeometryAI**, this is not needed: the rotating zone can cut straight through the geometry. The surface mesher splits every surface that crosses the zone boundary into the part inside the zone and the part outside, and the boundary conditions follow automatically.\n",
"\n",
"This notebook adds a nacelle behind the five-bladed isolated propeller used in other Flow360 examples:\n",
"\n",
"- a cylindrical rotating zone wraps the blades and the spinner and ends 0.1 m behind the spinner, cutting through the nacelle,\n",
"- GeometryAI splits the nacelle at the zone boundary into a part inside the zone and a part outside,\n",
"- the blades and the spinner rotate with the zone, while the piece of nacelle inside the zone is kept stationary,\n",
"- a single `Wall` boundary condition on all surfaces covers every part,\n",
"- a steady multiple reference frame (MRF) simulation then gives the thrust and torque of the propeller.\n",
"\n",
"\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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"## 1. Create the Project\n",
"\n",
"The geometry is an Engineering Sketch Pad (`.csm`) file downloaded from the example database. Its length unit is metres, and the flow comes from the negative x side:\n",
"\n",
"- the propeller has a diameter of 3.0 m and turns about the x axis,\n",
"- the parabolic spinner has a base radius of 0.2 m and runs from x = -0.25 m to x = 0.15 m,\n",
"- the nacelle continues the spinner with the same radius up to x = 1.25 m and closes with a parabolic tail at x = 1.85 m.\n",
"\n",
"The blades, the spinner and the nacelle form a single solid body."
]
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"[08:55:18] INFO : The file ( isolated_propeller_nacelle.csm) is being downloaded, please wait. \n",
"[08:55:36] INFO : Geometry successfully submitted: \n",
" type = Geometry \n",
" name = Propeller with nacelle, rotating zone with GeometryAI \n",
" id = geo-0f7a4d1f-e99f-4620-a6ca-97c4d78e4be6 \n",
" status = uploaded \n",
" project id = prj-3a7fae2a-9834-4065-880a-f8737797fe21 \n",
" \n",
" INFO : Waiting for geometry to be processed. \n",
"[08:56:13] INFO : Regrouping face entities under `faceName` tag ( previous `faceId`) . \n",
" INFO : Creating draft with geometry grouping: \n",
" faces: faceName \n",
" edges: edgeId \n",
" bodies: groupByFile \n",
" \n",
" INFO : using: SI unit system for unit inference. \n",
" INFO : using: SI unit system for unit inference. \n",
" INFO : using: SI unit system for unit inference. \n",
"[08:56:14] INFO : Selecting beta/in-house mesher for possible meshing tasks. \n",
" INFO : Using the Geometry AI surface mesher. \n",
"[08:56:16] INFO : Successfully submitted: \n",
" type = Case \n",
" name = Propeller with nacelle, J = 0.8 \n",
" id = case-d49c2eed-4312-408c-a61d-a0097c29806f \n",
" status = pending \n",
" project id = prj-3a7fae2a-9834-4065-880a-f8737797fe21 \n",
" \n",
"[09:15:46] INFO : Saved to /tmp/tmphky1tbx2/ dd6519aa-ee74-481a-a30c-36f82ce0dc22.csv \n",
""
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"source": [
"case.wait()\n",
"\n",
"residuals = case.results.nonlinear_residuals.as_dataframe()\n",
"residuals.plot(\"pseudo_step\", [\"0_cont\", \"1_momx\", \"2_momy\", \"3_momz\", \"4_energ\", \"5_nuHat\"], logy=True)\n",
"plt.show()"
]
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"## 8. The Split Surfaces\n",
"\n",
"The surface forces are reported for each boundary of the volume mesh, prefixed with the name of its zone, so they show what GeometryAI did:\n",
"\n",
"- the blades and the spinner lie entirely inside the rotating zone, so they appear with the suffix `__rotating_rotor`,\n",
"- the nacelle appears twice: under its own name in the stationary zone for the part behind the cut, and with the suffix `__rotating_rotor` for the part inside the rotating zone.\n",
"\n",
"The force coefficients are converted to a force along x and a moment about x with the dynamic pressure, the reference area and the moment length."
]
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"[09:15:48] INFO : Saved to /tmp/tmphky1tbx2/ 09e3aaad-d57d-46f9-92f7-9f7454b85f2f.csv \n",
"\n",
"\n",
"
\n",
" \n",
" \n",
" Fx [N] \n",
" Mx [N*m] \n",
" \n",
" \n",
" \n",
" \n",
" farfield/nacelle \n",
" 5.31 \n",
" 0.00 \n",
" \n",
" \n",
" rotor/blade1__rotating_rotor \n",
" -175.44 \n",
" -90.24 \n",
" \n",
" \n",
" rotor/blade2__rotating_rotor \n",
" -170.93 \n",
" -88.00 \n",
" \n",
" \n",
" rotor/blade3__rotating_rotor \n",
" -171.55 \n",
" -88.46 \n",
" \n",
" \n",
" rotor/blade4__rotating_rotor \n",
" -172.93 \n",
" -89.05 \n",
" \n",
" \n",
" rotor/blade5__rotating_rotor \n",
" -175.36 \n",
" -90.02 \n",
" \n",
" \n",
" rotor/nacelle__rotating_rotor \n",
" 0.21 \n",
" 0.00 \n",
" \n",
" \n",
" rotor/spinner__rotating_rotor \n",
" 0.12 \n",
" -0.04 \n",
" \n",
" \n",
"
\n",
"