Application of a K-ε Turbulence Model to Natural Convection From a Vertical Isothermal Surface

1977 ◽  
Vol 99 (1) ◽  
pp. 79-85 ◽  
Author(s):  
O. A. Plumb ◽  
L. A. Kennedy
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Turbulence Model ◽  
Energy Dissipation Rate ◽  
Convective Boundary ◽  
Wall Functions ◽  
Isothermal Surface ◽  
Turbulent Momentum ◽  
Energy Equations

A K-ε turbulence model similar to that proposed by Jones and Launder is applied to the calculation of the turbulent natural convective boundary layer on a vertical, isothermal surface. Conservation equations for the turbulent kinetic energy, dissipation rate of turbulent kinetic energy, and mean square temperature fluctuations are solved numerically along with the turbulent momentum and energy equations using the Spalding-Patankar boundary layer method. Various model constants and wall functions, and wall terms were tested. The results are compared with available experimental data and found to be in reasonable agreement.

Derivation of Turbulent Kinetic Energy from a First-Order Nonlocal Planetary Boundary Layer Parameterization

2013 ◽  
Vol 70 (6) ◽  
pp. 1795-1805 ◽  
Author(s):  
Hyeyum Hailey Shin ◽  
Song-You Hong ◽  
Yign Noh ◽  
Jimy Dudhia
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Planetary Boundary Layer ◽  
Water Cycle ◽  
Convective Boundary ◽  
First Order ◽  
Eddy Simulation ◽  
Pbl Parameterization ◽  
Planetary Boundary Layer Parameterization

Abstract Turbulent kinetic energy (TKE) is derived from a first-order planetary boundary layer (PBL) parameterization for convective boundary layers: the nonlocal K-profile Yonsei University (YSU) PBL. A parameterization for the TKE equation is developed to calculate TKE based on meteorological profiles given by the YSU PBL model. For this purpose buoyancy- and shear-generation terms are formulated consistently with the YSU scheme—that is, the combination of local, nonlocal, and explicit entrainment fluxes. The vertical transport term is also formulated in a similar fashion. A length scale consistent with the K profile is suggested for parameterization of dissipation. Single-column model (SCM) simulations are conducted for a period in the second Global Energy and Water Cycle Experiment (GEWEX) Atmospheric Boundary Layer Study (GABLS2) intercomparison case. Results from the SCM simulations are compared with large-eddy simulation (LES) results. The daytime evolution of the vertical structure of TKE matches well with mixed-layer development. The TKE profile is shaped like a typical vertical velocity (w) variance, and its maximum is comparable to that from the LES. By varying the dissipation length from −23% to +13% the TKE maximum is changed from about −15% to +7%. After normalization, the change does not exceed the variability among previous studies. The location of TKE maximum is too low without the effects of the nonlocal TKE transport.

scholarly journals A Scale-Adaptive Turbulent Kinetic Energy Closure for the Dry Convective Boundary Layer

2018 ◽  
Vol 75 (2) ◽  
pp. 675-690 ◽  
Author(s):  
Marcin J. Kurowski ◽  
João Teixeira
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Convective Boundary Layer ◽  
Mixing Length ◽  
Subgrid Scale ◽  
Convective Boundary ◽  
Continuous Transition ◽  
Simple Method ◽  
Grid Length

Abstract A pragmatic scale-adaptive turbulent kinetic energy (TKE) closure is proposed to simulate the dry convective boundary layer for a variety of horizontal grid resolutions: from 50 m, typical of large-eddy simulation models that use three-dimensional turbulence parameterizations/closures, up to 100 km, typical of climate models that use one-dimensional turbulence and convection parameterizations/closures. Since parameterizations/closures using the TKE approach have been frequently used in these two asymptotic limits, a simple method is proposed to merge them with a mixing-length-scale formulation for intermediate resolutions. This new scale-adaptive mixing length naturally increases with increasing grid length until it saturates as the grid length reaches mesoscale-model resolution. The results obtained using this new approach for dry convective boundary layers are promising. The mean vertical profiles of potential temperature and heat flux remain in good agreement for different resolutions. A continuous transition (in terms of resolution) across the gray zone is illustrated through the partitioning between the model-resolved and the subgrid-scale transports as well as by documenting the transition of the subgrid-scale TKE source/sink terms. In summary, a natural and continuous transition across resolutions (from 50 m to 100 km) is obtained, for dry convection, using exactly the same atmospheric model for all resolutions with a simple scale-adaptive mixing-length formulation.

scholarly journals THE BOTTLENECK PROBLEM FOR TURBULENCE IN RELATION TO SUSPENDED SEDIMENT IN THE SURF ZONE

1986 ◽  
Vol 1 (20) ◽  
pp. 90
Author(s):  
Peter Justensen ◽  
Jorgen Fredsoe ◽  
Rolf Deigaard
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Energy Level ◽  
Vertical Distribution ◽  
Turbulent Kinetic Energy ◽  
Suspended Sediment ◽  
Turbulence Model ◽  
Surf Zone ◽  
Wave Boundary ◽  
The Vertical Distribution

In the present paper the vertical distribution of turbulent kinetic energy k under broken waves is calculated by application of a one-equation turbulence model. The contributions to the energy level originate partly from the production in the wave boundary layer, partly from the production in the roller. Further on, the findings for k are used to calculate the vertical distribution of suspended sediment in broken waves.

scholarly journals Turbulence measurements with a tethered balloon

2016 ◽  
Author(s):  
G. Canut ◽  
F. Couvreux ◽  
M. Lothon ◽  
D. Legain ◽  
B. Piguet ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Convective Boundary Layer ◽  
Motion Sensor ◽  
Tethered Balloon ◽  
Inertial Motion ◽  
Convective Boundary ◽  
Momentum Fluxes ◽  
Field Campaigns

Abstract. This study presents the first deployment of a turbulence probe below a tethered balloon in field campaigns. This system allows to measure turbulent temperature fluxes, momentum fluxes as well as turbulent kinetic energy in the lower part of the boundary layer. It is composed of a sonic thermoanemometer and inertial motion sensor. It has been validated during three campaigns with different convective boundary layer conditions using turbulent measurements from atmospheric towers and aircraft.

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