HarryvL wrote: ↑
Sat Mar 24, 2018 1:16 pm
Thomas, did you rerun the antenna assembly? Could you describe workflow and results please? I would be interested to know what the effective drag of the assembly is. Thanks. Harry
model-scale 1:1, antenna-lenghts 2,0 m, type Kathrein K80010865, according to
http://www.kathreinusa.com/wind-load-sc ... ttom-line/
mesher: cfmesh, 350000 cells, meshing time 290 sec.
solver: simpleFoam, steady, incompressible, turbulence-model k-omega SST. runtime 3,5 hours.
fluid: air, density 1,25 kg/m^3.
inlet-speed 42 m/s (=150 km/h, according to Kathrein datasheets).
After 700 Iterations the residuals remain stable and the results dont change any more.
In paraview you can calculate the drag-force by using several filters.
The drag_x on the whole cluster is 1707 N. When doing a calculation "by hand" with an approach I
normally uses in my statics-calculation (1x frontal loading on antenna, 2x rear under 45 deg + tubes)
I get 1663 N. The error is below 3%. From a scientific point of view the simulation can be done better
(much finer mesh, more boundary-layers, mesh-refinement in downstream region, bigger computing domain and...)
but I must find a compromise due to my not so sophisticated computer.
turbulence-parameters: I found out that I get the "best" results when using the default parameters
in the input dialogs.
To be done: simulating the effect of cable-packages / ladders on the antenna structure.