We study the stability of steady convection rolls in two-dimensional Rayleigh–Bénard with free-slip boundaries and horizontal periodicity over 12 orders magnitude Prandtl number $(10^{-6} \leq Pr 10^6)$ 6 Rayleigh $(8{\rm \pi} ^4 < Ra 10^8)$ . The analysis is facilitated by partitioning our modal expansion into so-called even odd modes. With aspect ratio $\varGamma = 2$ , we observe that zon...

The exponentially decaying behavior of the momentum-momentum and momentumforce time correlation functions of Brownian motion at large times has been extensively used for the numerical evaluation of the friction coefficient γ from molecular dynamics simulations. We perform numerical analysis on these methods and address issues related to the appropriate choice of large time and the rate of conve...

We present a new lensless incoherent holographic system operating in a synthetic aperture mode. Spatial resolution exceeding the Rayleigh limit of the system is obtained by tiling digitally several Fresnel holographic elements into a complete Fresnel hologram of the observed object. Each element is acquired by the limited-aperture system from different point of view. This method is demonstrated...

Improved spectral measurements of the narrow spike in the high resolution hyper-Rayleigh light scattering spectrum for deuterated liquid nitrobenzene (C(6)D(5)NO(2)) doped with triflic acid (CF(3)SO(3)H) determined that the reorientation time for the dopant-induced polar domains is 2.9 micros in the dilute limit. Two models based on ions dissolved in nitrobenzene fit the measured spectral broad...

The parameter dependence of the various attractive solutions of the three variable nonlinear Lorenz model equations for thermal convection in Rayleigh-Bénard flow is studied. Its bifurcation structure has commonly been investigated as a function of r, the normalized Rayleigh number, at fixed Prandtl number σ. The present work extends the analysis to the entire (r, σ) parameter plane. An onion l...

The problem of scattering of ultrasound by particles in the long wavelength limit has a well-established solution in terms of Rayleigh expansions of the scattered fields. However, this solution is ill-conditioned numerically, and recent work has attempted to identify an alternative method. The scattered fields have been expressed as a perturbation expansion in the parameter Ka (the wavenumber m...

Turbulent motions in the interior of a star play an important role in its evolution, since they transport chemical species, thermal energy and angular momentum. Our overall goal is to construct a practical turbulent closure model for convective transport that can be used in a multidimensional stellar evolution calculation including the effects of rotation, shear and magnetic fields. Here, we fo...