Order parameter equation and model equation for high Prandtl number. Rayleigh-B�nard convection in a rotating large aspect ratio system

1993 ◽  
Vol 92 (2) ◽  
pp. 243-256 ◽  
Author(s):  
M. Neufeld ◽  
R. Friedrich ◽  
H. Haken
Keyword(s):  
Aspect Ratio ◽  
Prandtl Number ◽  
Order Parameter ◽  
Model Equation ◽  
Large Aspect Ratio ◽  
Parameter Equation ◽  
High Prandtl Number

Instability and associated roll structure of Marangoni convection in high Prandtl number liquid bridge with large aspect ratio

2015 ◽  
Vol 27 (2) ◽  
pp. 024108 ◽  
Author(s):  
T. Yano ◽  
K. Nishino ◽  
H. Kawamura ◽  
I. Ueno ◽  
S. Matsumoto
Keyword(s):  
Aspect Ratio ◽  
Prandtl Number ◽  
Liquid Bridge ◽  
Marangoni Convection ◽  
Large Aspect Ratio ◽  
High Prandtl Number

scholarly journals HEXAGONAL PATTERNS IN A MODEL FOR ROTATING CONVECTION

2004 ◽  
Vol 14 (01) ◽  
pp. 107-117 ◽  
Author(s):  
S. MADRUGA ◽  
C. PÉREZ-GARCÍA
Keyword(s):  
Prandtl Number ◽  
Rotation Rate ◽  
Short Wavelength ◽  
Model Equation ◽  
Amplitude Equation ◽  
Temperature Dependent ◽  
Weakly Nonlinear ◽  
Weakly Nonlinear Analysis ◽  
High Prandtl Number ◽  
Temperature Dependent Properties

We study a model equation that mimics convection under rotation in a fluid with temperature-dependent properties (non-Boussinesq (NB)), high Prandtl number and idealized boundary conditions. It is based on a model equation proposed by Segel [1965] by adding rotation terms that lead to a Küppers–Lortz instability [Küppers & Lortz, 1969] and can develop into oscillating hexagons. We perform a weakly nonlinear analysis to find out explicitly the coefficients in the amplitude equation as functions of the rotation rate. These equations describe hexagons and oscillating hexagons quite well, and include the Busse–Heikes (BH) model [Busse & Heikes, 1980] as a particular case. The sideband instabilities as well as short wavelength instabilities of such hexagonal patterns are discussed and the threshold for oscillating hexagons is determined.

Large-Aspect-Ratio Structures in Simulated Ocean Surface Boundary Layer Turbulence under a Hurricane

2020 ◽  
Vol 50 (12) ◽  
pp. 3561-3584
Author(s):  
Clifford Watkins ◽  
Daniel B. Whitt
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Aspect Ratio ◽  
Prandtl Number ◽  
Ocean Surface ◽  
Surface Boundary ◽  
Large Aspect Ratio ◽  
Surface Boundary Layer ◽  
Velocity Magnitude ◽  
The Mean

AbstractA large-eddy simulation (LES) initialized and forced using observations is used to conduct a process study of ocean surface boundary layer (OSBL) turbulence in a 2-km box of ocean nominally under Hurricane Irene (2011) in 35 m of water on the New Jersey shelf. The LES captures the observed deepening, cooling, and persistent stratification of the OSBL as the storm approaches and passes. As the storm approaches, surface-intensified Ekman-layer rolls, with horizontal wavelengths of about 200 m and horizontal-to-vertical aspect and velocity magnitude ratios of about 20, dominate the kinetic energy and increase the turbulent Prandtl number from about 1 to 1.5 due partially to their restratifying vertical buoyancy flux. However, as the storm passes, these rolls are washed away in a few hours due to the rapid rotation of the wind. In the bulk OSBL, the gradient Richardson number of the mean profiles remains just above (just below) 1/4 as the storm approaches (passes). At the base of the OSBL, large-aspect-ratio Kelvin–Helmholtz billows, with Prandtl number below 1, intermittently dominate the kinetic energy. Overall, large-aspect-ratio covariance modifies the net vertical fluxes of buoyancy and momentum by about 10%, but these fluxes and the analogous diffusivity and viscosity still approximately collapse to time-independent dimensionless profiles, despite rapid changes in the forcing and the large structures. That is, the evolutions of the mean temperature and momentum profiles, which are driven by the net vertical flux convergences, mainly reflect the evolution of the wind and the initial ocean temperature profile.

HEAT TRANSFER IN A FLAT CHANNEL WITH HIGH ASPECT RATIO AT A HEAT CARRIER FLOW WITH LOW-PRANDTL NUMBER

2018 ◽  
Author(s):  
Viktor S. Naumkin ◽  
O.V. Vitovsky ◽  
Maksim S. Makarov ◽  
V. E. Nakoryakov
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Prandtl Number ◽  
Heat Carrier ◽  
High Aspect Ratio ◽  
Flat Channel ◽  
Carrier Flow

scholarly journals Structural Design and Analysis of Flat LOFT Apartment with Large Aspect Ratio

2018 ◽  
Vol 439 ◽  
pp. 042070
Author(s):  
Junjie Chen ◽  
Mufeng Chen ◽  
Zhixiong Lu
Keyword(s):  
Aspect Ratio ◽  
Structural Design ◽  
Large Aspect Ratio

Experimental and numerical investigation on inner flow and spray characteristics of elliptical GDI injectors with large aspect ratio

Energy ◽  
2021 ◽  
Vol 224 ◽  
pp. 120119
Author(s):  
Shenghao Yu ◽  
Bifeng Yin ◽  
Qinsheng Bi ◽  
Chen Chen ◽  
Hekun Jia
Keyword(s):  
Aspect Ratio ◽  
Numerical Investigation ◽  
Large Aspect Ratio ◽  
Spray Characteristics

Lubrication Performance Distribution of Large Aspect Ratio Water-Lubricated bearings Considering Deformation and Shaft Bending

2021 ◽  
pp. 1-15
Author(s):  
Wu Ouyang ◽  
Qichao Cheng ◽  
Yong Jin ◽  
Qilin Liu ◽  
Bin Wang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Large Aspect Ratio ◽  
Lubrication Performance ◽  
Performance Distribution
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