Reversals of coherent structures in turbulent mixed convection
نویسندگان
چکیده
منابع مشابه
Wind reversals in turbulent Rayleigh-Bénard convection.
The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-Bénard convection is theoretically analyzed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range 10(-2)...
متن کاملEffect of large-scale coherent structures on turbulent convection.
We study an effect of large-scale coherent structures on global properties of turbulent convection in laboratory experiments in air flow in a rectangular chamber with aspect ratios A approximately 2 and A approximately 4 (with the Rayleigh numbers varying in the range from 5x10;{6} to 10;{8} ). The large-scale coherent structures comprise the one-cell and two-cell flow patterns. We found that a...
متن کاملDynamics and symmetries of flow reversals in turbulent convection.
Based on direct numerical simulations and symmetry arguments, we show that the large-scale Fourier modes are useful tools to describe the flow structures and dynamics of flow reversals in Rayleigh-Bénard convection (RBC). We observe that during the reversals, the amplitude of one of the large-scale modes vanishes, while another mode rises sharply, very similar to the "cessation-led" reversals o...
متن کاملOnset of coherent oscillations in turbulent Rayleigh-Bénard convection.
We report temperature cross correlation and velocity profile measurements in the aspect-ratio-one convection cell filled with water. A sharp transition from a random chaotic state to a correlated turbulent state of finite coherence time is found when the Rayleigh number becomes larger than a critical value Ra(c) approximately equal to 5 x 10(7). The experiment reveals a unique mechanism for the...
متن کاملExact Coherent Structures in Turbulent Shear Flows
Exact coherent structures are three-dimensional, nonlinear traveling wave solutions of the Navier-Stokes equations. These solutions are typically unstable from onset, yet they capture the basic statistical and structural features of low Reynolds number turbulent shear flows remarkably well. These exact coherent structures have now been found in all canonical shear flows: plane Couette, Poiseuil...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Fluid Mechanics
سال: 2020
ISSN: 0022-1120,1469-7645
DOI: 10.1017/jfm.2020.705