Effect of Low-Frequency Modulation on Thermal Convection Instability
نویسندگان
چکیده
The stability of a horizontal layer of fluid heated from below is examined when, in addition to a steady temperature difference between the horizontal walls of the layer a time-dependent low-frequency per turbation is applied to the wall temperatures. An asymptotic solution is obtained which describes the be haviour of infinitesimal disturbances to this configuration. Possible stability criteria are analyzed and the results are compared with the known experimental as well as numerical results.
منابع مشابه
Effect of Modulation on Thermal Convection Instability
The linear stability problem for a fluid in a classic Benard configuration is considered. The applied temperature gradient is the sum of a steady component and a time-dependent periodic component. Only infinitesimal disturbances are considered. The time-dependent perturbation is expressed in Fourier series. The shift in critical Rayleigh number is calculated and the modulating effect of the osc...
متن کاملInvestigation on Instability of Rayleigh-Benard Convection Using Lattice Boltzmann Method with a Modified Boundary Condition
In this study, the effects of Prandtl number on the primary and secondary instability of the Rayleigh-Benard convection problem has been investigated using the lattice Boltzmann method. Two different cases as Pr=5.8 and 0.7 representing the fluid in liquid and gas conditions are examined. A body forces scheme of the lattice Boltzmann method was presented. Two types of boundary conditions in the...
متن کاملThermal g-modes and unexpected convection in superfluid neutron stars
We suggest that specific thermal low-frequency g-modes can exist in superfluid neutron stars. They can be excited in the matter with a nonzero gradient of entropy per electron. We determine the Brunt-Väisälä frequency for these modes and demonstrate that they can be unstable with respect to convection. The criterion for the instability onset (analogue of the well-known Schwarzschild criterion) ...
متن کاملParametric Instability in Long Optical Cavities and Suppression by Dynamic Transverse Mode Frequency Modulation
Three mode parametric instability has been predicted in Advanced gravitational wave detectors. Here we present the first observation of this phenomenon in a large scale suspended optical cavity designed to be comparable to those of advanced gravitational wave detectors. Our results show that previous modelling assumptions that transverse optical modes are stable in frequency except for frequenc...
متن کاملEffect of Variable Thermal Expansion Coefficient and Nanofluid Properties on Steady Natural Convection in an Enclosure
Steady state natural convection is numerically investigated in an enclosure using variable thermal conductivity, viscosity and thermal expansion coefficient of Al2O3–water nanofluid. This study has been conducted for a wide range of Rayleigh numbers (103≤ Ra ≤ 106), concentrations of nanoparticles (0% ≤ Φ ≤ 7%), enclosure aspect ratios (0.5 ≤ AR ≤ 2) and temperature differences between the cold...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001