Transcript Channel flow benchmarks

Channel flow benchmarks
•
DNS datasets to validate Code_Saturne
•
Effect of complex grids
 hexa, non-conform, tetra
•
Low Reynolds number tests Ret = 100
 no turbulence model
•
Ret = 395 tests
 subgrid scale model tests
•
Towards high Reynolds numbers
 subgrid scale models at high Reynolds
numbers
Channel flow benchmarks: « classic » DNS
•
DNS Ret = 180
•
Box 4 x 2 x 2, Grid 192 x 128 x 160 (4M cells)
 Same grid as Mansour, Kim & Moin
•
Results include
 velocity, shear and normal stresses (<u>, <u’v’> etc… )
 Triple correlations (<v’u’u’> etc…)
 Terms in turbulent kinetic energy budget
 Terms in the components of each budget
Channel flow benchmarks: DNS Ret =180
• Grid adapted for a
spectral code
• but applied to a non
spectral code
Channel flow benchmarks: DNS Ret =180
• Grid adapted for a spectral code
• but applied to a non spectral code
Channel flow benchmarks: DNS Ret =180
• Grid adapted for a spectral code
• but applied to a non spectral code
Channel flow benchmarks: DNS Ret =180
Channel flow benchmarks: DNS Ret =180
Channel flow benchmarks: DNS Ret =180
Channel flow benchmarks: Code_Saturne test grids
Hexahedral
Non-conform (hexa)
Box 2 x 2 x 
440,000 elements
Tetrahedral
Channel flow benchmarks: Ret = 100
• DNS 880k cells
 for same box size
• tests 440k cells
• Tetra
 poorly resolved
 difference in grid on
each wall
• Hexa
too coarse at wall
Channel flow benchmarks: Ret = 100
• turbulence kinetic energy
• weaknesses of each case become more clear
Channel flow benchmarks: Ret = 395
• velocity
Channel flow benchmarks: Ret = 395
• shear stress
Channel flow benchmarks: Ret = 395
• normal stresses
Channel flow benchmarks: Ret = 395
• tke
Channel flow benchmarks: high Reynolds numbers
• Box 6 x 2 x2, Grid 11 x 11 x 11 (1.3k cells)
Detail of the tubes that make up a bundle inside a SFR reactor
Thermal
radiation

Ensure the tubes don’t touch,
Ensure that sodium cannot get trapped (particularly
important with respect to the neutronic reactions),
 Reduce vibrations within the tube bundle,
Improve the mixing near the heater and increase the rate
of heat exchange.
First attempts to simulate the fluid
A z=100mm
A z=140mm