filmov
tv
2022-06 - Energy Dissipator - k-omega vs RNG k-epsilon
Показать описание
The simulation and discussion here are qualitative just to make some fun during the long Lunar New Year holiday with strict social distancing restrictions to curb spreading of Omicron in Hong Kong.
My previous CFD simulation "2022-05 - Energy Dissipator - Tumbling Flow in Box Culvert" was carried out using "k-omega" turbulence model. This animation compares the same energy dissipator simulation by using another commonly used turbulence model "RNG k-epsilon" in Flow 3D.
For RANS model, closure of the set of governing equations requires turbulence model. However, turbulence model is semi-empirical which requires insight to propose some terms in turbulence model and coefficients calibrated by experimental results. Therefore, different turbulence models have pros and cons in different areas of application.
Results obtained from the two turbulence models appear quite different at a first glimpse. k-omega model (upper one) gives wavy and spiky water surface, while RNG k-epsilon model (lower one) gives smooth surface showing clearly ups and downs for flow passing through roughness elements. I think that k-omega gives flow behaviour closer to reality as I tried to run LES on the same problem to obtain similar results qualitatively. RNG k-epsilon appears to average out wavy water surface to give average flow behaviour.
As a civil engineer, RNG k-epsilon model seems okay for drainage design by inspecting average flow depth and velocity. I guess unless instantaneous fluctuation of pressure or flow separation at roughness elements are of concern, k-omega model may be more suitable.
My previous CFD simulation "2022-05 - Energy Dissipator - Tumbling Flow in Box Culvert" was carried out using "k-omega" turbulence model. This animation compares the same energy dissipator simulation by using another commonly used turbulence model "RNG k-epsilon" in Flow 3D.
For RANS model, closure of the set of governing equations requires turbulence model. However, turbulence model is semi-empirical which requires insight to propose some terms in turbulence model and coefficients calibrated by experimental results. Therefore, different turbulence models have pros and cons in different areas of application.
Results obtained from the two turbulence models appear quite different at a first glimpse. k-omega model (upper one) gives wavy and spiky water surface, while RNG k-epsilon model (lower one) gives smooth surface showing clearly ups and downs for flow passing through roughness elements. I think that k-omega gives flow behaviour closer to reality as I tried to run LES on the same problem to obtain similar results qualitatively. RNG k-epsilon appears to average out wavy water surface to give average flow behaviour.
As a civil engineer, RNG k-epsilon model seems okay for drainage design by inspecting average flow depth and velocity. I guess unless instantaneous fluctuation of pressure or flow separation at roughness elements are of concern, k-omega model may be more suitable.
0:00:26
2022-06 - Energy Dissipator - k-omega vs RNG k-epsilon
0:00:26
2022-07 - Energy Dissipator - Tumbling Flow in Circular Culvert
0:00:41
2022-09 - Energy Dissipator - Stilling Basin with Free Hydraulic Jump
0:00:26
2022-05 - Energy Dissipator - Tumbling Flow in Box Culvert
0:00:41
2022-10 - Energy Dissipator - SAF Stilling Basin
0:00:06
Energy Dissipation Test System / Enerji Dağılım Test Cihazı
0:00:53
2020-06 - Energy Dissipation Chamber of Vortex Drop Shaft (2 of 2)
0:00:06
Flip Bucket Type Energy Dissipator: Modelling and Simulation using FLOW-3D
0:00:51
2017-07 - Hydraulic Energy Dissipation by Impact Type Stilling Basin (Fr = 4)
0:00:51
2017-07 - Hydraulic Energy Dissipation by Impact Type Stilling Basin (Fr = 2)
0:08:52
Roller bucket type energy dissipator
0:00:31
Energy Dissipation Simulation | FLOW-3D HYDRO
0:00:13
Study of Energy Dissipation on Steep Sloping Channel using CFD | OpenFOAM | CFD for Water
0:00:51
2018-04 - Hydraulic Energy Dissipation by USBR Type IX Baffled Apron
0:00:26
Energy Dissipator in Dam #energy #civilengineering #engineering #trending #shorts
1:04:05
Euler flows with local energy dissipation - Hyunju Kwon
0:10:15
Hydraulic Analysis of Ski Jump as An Energy Dissipator
0:13:01
Basic of a CMOS -Inverter configuration, Transmission gate nd Power dissipation
0:00:41
Hydraulic Energy Dissipation by Stilling Basin with Hydraulic Jump
0:00:11
Outlet Pool with Energy Dissipation
0:02:07
Energy dissipation pressure sewer discharge chamber
0:00:45
Energy Dissipation Chamber
0:00:41
Energy dissipation structure in an open channel
0:02:56
Drop Shafts and Energy Dissipators
Комментарии