Difference between revisions of "Isotropic Mesh Generation"
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== Refinement of Nacelle Engine, Rocket, and Launch Vehicle with Two Boosters (lv2b) == | == Refinement of Nacelle Engine, Rocket, and Launch Vehicle with Two Boosters (lv2b) == | ||
| + | |||
| + | === Input Surface Meshes === | ||
<div><ul> | <div><ul> | ||
<li style="display: inline-block;"> [[File: nacelle6.png|thumb|none|450px]] </li> | <li style="display: inline-block;"> [[File: nacelle6.png|thumb|none|450px]] </li> | ||
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<br><br><br> | <br><br><br> | ||
| + | === Parameters === | ||
{| class="wikitable" style="text-align:center;" | {| class="wikitable" style="text-align:center;" | ||
|+ Parameters for unstructured grid generation. Additional parameters only for CDT3D: nthreads : 12 (parallel); nthreads : 1 (sequential); nbuckets : 240; frbtransf : 0.3; cbtransf : 1.0. Additional parameters only for AFLR: mrecrbf : 0. | |+ Parameters for unstructured grid generation. Additional parameters only for CDT3D: nthreads : 12 (parallel); nthreads : 1 (sequential); nbuckets : 240; frbtransf : 0.3; cbtransf : 1.0. Additional parameters only for AFLR: mrecrbf : 0. | ||
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<br><br> | <br><br> | ||
| + | === Results === | ||
{| class="wikitable" style="text-align:center;" | {| class="wikitable" style="text-align:center;" | ||
|+ Evaluation results on unstructured grid generation. CDT3D is compared with state-of-the-art technology AFLR v16.9.19. CDT3D’s runs are performed with 1 and 12 hardware cores. AFLR is a sequential code. This table lists the parameters of the evaluation. The sliver elements have a dihedral angle smaller than 2° or larger than 178°. The initial grid includes Delaunay tetrahedralization and Boundary Recovery. The I/O time is not included. The experiments were performed on a Dell workstation with Linux Ubuntu 12.10, using a 12-core Intel Xeon CPU X5690@3.47 GHz, and 96 GB RAM. | |+ Evaluation results on unstructured grid generation. CDT3D is compared with state-of-the-art technology AFLR v16.9.19. CDT3D’s runs are performed with 1 and 12 hardware cores. AFLR is a sequential code. This table lists the parameters of the evaluation. The sliver elements have a dihedral angle smaller than 2° or larger than 178°. The initial grid includes Delaunay tetrahedralization and Boundary Recovery. The I/O time is not included. The experiments were performed on a Dell workstation with Linux Ubuntu 12.10, using a 12-core Intel Xeon CPU X5690@3.47 GHz, and 96 GB RAM. | ||
Revision as of 04:47, 28 March 2018
Contents
Sphere
Cuts of tetrahedral grids of a sphere generated for varied cdfm ∈ [0, 1]. Blue
corresponds to larger values of the distribution function. Red corresponds to smaller values
of the distribution function.
Element angle distribution (in 5-deg increments) of grids of sphere, for varied
cdfm.
The dihedral angle extrema and the element count are reported for each grid.
Two Blades with Merging Wakes and a Symmetry Plane
Cuts of tetrahedral grids of two blades with merging wakes and a symmetry
plane enclosed in an outer boundary generated for varied cdfm ∈ [0, 1] (shown in
(c)-(f)).
The input surface is depicted in (a)-(b). The wake region is modeled as an embedded/
transparent delete surface.
Element angle distribution (in 5-deg increments) of grids of two blades with
merging wakes and a symmetry plane enclosed in an outer boundary, for varied cdfm.
The
dihedral angle extrema and the element count are reported for each grid.
Refinement of Nacelle Engine, Rocket, and Launch Vehicle with Two Boosters (lv2b)
Input Surface Meshes
- Surface grid of an aircraft nacelle with engine inside a section of wind tunnel.
- #points: 27184; #triangles: 54360
- Surface grid of a rocket with engine, nozzle and transparent internal data surfaces inside flow field.
- #points: 20228; #triangles: 40448
- Surface grid of a launch vehicle with solid boosters inside flow field (Lv2b).
- #points: 42020; #triangles: 84024
Parameters
| Geometry | Software | cdfm | cdfn | mrecm | nqual | csmth | msmth | nsmth | angdfs | angqual | mdbs | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nacelle | CDT3D | 0.291 | 0.7 | 2 | 3 | 0.5 | 1 | 2 | 165° | 120° | 0 | |||||||||||
| AFLR | 0.50 | 0.7 | 2 | 3 | 0.5 | 1 | 2 | 165° | 120° | 0 | ||||||||||||
| Rocket | CDT3D | 0.20 | 0.7 | 2 | 3 | 0.5 | 1 | 2 | 165° | 120° | 0 | |||||||||||
| AFLR | 0.60 | 0.7 | 2 | 3 | 0.5 | 1 | 2 | 165° | 120° | 0 | ||||||||||||
| Lv2b | CDT3D | 0.234 | 0.7 | 2 | 3 | 0.5 | 1 | 2 | 165° | 120° | 0 | |||||||||||
| AFLR | 0.30 | 0.7 | 2 | 3 | 0.5 | 1 | 2 | 165° | 120° | 0 | ||||||||||||
Results
| Case | Software | #Cores | %Slivers (w/o improv.) (x10-3) |
#Tets (w/ improv.) (M) |
Min/Max Angle (w/ improv.) (deg) |
Initial Grid (sec) |
Refinement (min) |
Improvement (min) |
Total (min) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nacelle | CDT3D | 1 | 3.74 | 43.65 | 13.57°/153.44° | 1.36 | 20.01 | 14.30 | 34.33 | |||||||||
| CDT3D | 12 | 3.70 | 42.85 | 12.06°/159.52° | 1.36 | 5.02 | 18.59 | 23.64 | ||||||||||
| AFLR | 1 | 2.97 | 43.16 | 7.00°/164.86° | 5.63 | 22.59 | 6.40 | 29.09 | ||||||||||
| Rocket | CDT3D | 1 | 2.96 | 118.41 | 9.39°/159.30° | 1.58 | 52.85 | 64.56 | 117.44 | |||||||||
| CDT3D | 12 | 2.95 | 119.06 | 9.21°/158.33° | 1.58 | 14.51 | 68.23 | 82.76 | ||||||||||
| AFLR | 1 | 3.05 | 123.13 | 5.58°/164.75° | 6.76 | 131.89 | 25.41 | 157.42 | ||||||||||
| Lv2b | CDT3D | 1 | 5.09 | 98.21 | 6.60°/159.68° | 5.45 | 41.57 | 94.63 | 136.29 | |||||||||
| CDT3D | 12 | 4.69 | 113.99 | 8.24°/158.59° | 5.45 | 12.92 | 62.36 | 75.37 | ||||||||||
| AFLR | 1 | 3.49 | 104.10 | 6.84°/164.88° | 16.97 | 98.24 | 18.51 | 117.03 | ||||||||||
- Tetrahedral field cuts of the aircraft nacelle
- Detail views of tetrahedral field cuts of aircraft nacelle generated with CDT3D
- Tetrahedral field cuts of the rocket
- Tetrahedral field cuts of the Lv2b
- Element angle distribution (in 5-deg increments) of aircraft nacelle grids. The dihedral angle extrema are reported for each method.
- Element angle distribution (in 5-deg increments) after improvement of Rocket and Lv2b grids. The dihedral angle extrema are reported for each method.
- Slivers after the completion of refinement of the aircraft nacelle. Red represents elements whose minimum dihedral angle is smaller than 2◦ or larger than 178◦.
Refinement of DLR-F6 Airbus type aircraft
- Surface grid of a DLR-F6 Airbus type aircraft with anisotropic boundary layers on a symmetry plane;
- #points: 1006144; #triangles: 2012288
- Cuts of the tetrahedral grid of the flow field of DLR-F6 Airbus aircraft, generated with CDT3D. A smaller grid (≈200 M tetrahedra) is depicted due to limitations in visualization.
| nthreads | #Tets (Bi) |
%Slivers (w/o improv.) (x10-2) |
#Iter | Recon./Iter (min) |
Refinement (hours) |
Recon./Iter (Speedup) |
Refinement (Speedup) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.414 | 1.438 | 61 | 51.69 | 58.98 | 1 | 1 | |||||||||
| w/o sorting | 12 | 1.413 | 1.472 | 73 | 4.81 | 13.10 | 10.74 | 4.50 | ||||||||
| 24 | 1.455 | 1.563 | 83 | 2.51 | 11.81 | 20.59 | 5.00 | |||||||||
| 36 | 1.438 | 1.487 | 79 | 1.98 | 10.59 | 26.10 | 5.57 | |||||||||
| 48 | 1.451 | 1.556 | 118 | 1.84 | 14.36 | 28.09 | 4.10 | |||||||||
| w/ sorting | 12 | 1.414 | 1.563 | 89 | 3.99 | 17.38 (3.62) | 12.95 | 3.39 | ||||||||
| 24 | 1.439 | 1.499 | 75 | 1.98 | 12.74 (3.16) | 26.10 | 4.62 | |||||||||
| 36 | 1.458 | 1.518 | 93 | 1.67 | 14.87 (4.00) | 30.95 | 3.96 | |||||||||
| 48 | 1.448 | 1.625 | 122 | 1.39 | 18.77 (5.08) | 37.18 | 3.14 | |||||||||
