The large-scale flows of the oceans and atmosphere are driven by a non-uniform surface heating over latitude, rotation. For many years scientists try to understand these doing laboratory experiments. In present paper we discuss two rather new experiments designed study certain aspects atmospheric circulation. One experiments, differentially heated rotating annulus at Brandenburg University Technology (BTU) Cottbus, has cooled inner cylinder outer wall. However, structure meridional...

There is an ongoing debate in the literature about whether present global warming increasing local and temperature variability. The central methodological issues of this relate to proper treatment normalised anomalies trends studied time series which may be difficult separate from time-evolving fluctuations. Some argue that variability indeed globally, whereas others conclude it decreasing or remains practically unchanged. Meanwhile, a consensus appears emerge certain regions (e.g. Western...

Abstract The mechanism of localized inertial wave excitation and its efficiency is investigated for an annular cavity rotating with $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq \ge =\geqslant \geq \def \Pr {\mathit {Pr}}\def \Fr {Fr}}\def \Rey {Re}}\Omega _0$ . Meridional symmetry broken by replacing the inner cylinder a truncated cone (frustum). Waves are excited individual longitudinal libration walls. geometry non-separable exhibits focusing...

We propose a scheme for studying thin liquid films on solid substrate using phase field model. For van der Waals fluid---far from criticality---the most natural function is the fluid density. The theoretical description based Navier-Stokes equation with extra terms and continuity equation. In this model free of interface conditions, contact angle can be controlled through boundary conditions density at walls [L. M. Pismen Y. Pomeav, Phys. Rev. E 62, 2480 (2000)]. investigate stability film...

We discuss a mechanism for controlled motion of drops with applications microfluidics and microgravity. The is the following: solid plate supporting liquid droplet simultaneously subject to lateral vertical harmonic oscillations. In this way symmetry back-and-forth movement along substrate under inertial effects broken thus will induce net driven drop. study dependency traveled distance on oscillation parameters (forcing amplitude, frequency, phase shift between two perpendicular...

Abstract Surface waves of a shallow liquid layer confined in an annular channel length $${{\tilde{L}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>L</mml:mi> <mml:mo>~</mml:mo> </mml:mover> </mml:math> are generated by periodic acceleration the along its azimuthal direction. We show that if oscillations anharmonic, e.g., having form saw tooth, mean mass flow is and even speed over one period zero. The studied both experimentally numerically. In experiment,...

We investigate numerically the role of correlation length in drop behavior on noisy surfaces. To this aim, a phase field tool has been used. Theoretical results are confirmed by experiments distilled water drops sitting stainless steel and silicon surfaces textured laser-induced periodic self-organized structures: an increase noise amplitude amplification original (i.e., hydrophobic is getting more hydrophobic, hydrophilic hydrophilic). Furthermore, computer simulations two three spatial...

Inertial modes are excited in a fluid filled rotating annulus by modulating the rotation rate of outer cylinder and upper lower lids. This forcing leads to inertial wave beams being emitted from corner regions due periodic motions boundary layers. When frequency matches eigenfrequency beam pattern amplitude is increasing, broaden mode structures can be observed. The eigenmodes compared with analytical solutions corresponding inviscid problem. In particular for pressure field good agreement...

Abstract Surface wave resonance of a liquid (water) layer confined in circular channel is studied both experimentally and numerically. For the experiment, eight unevenly distributed ultrasonic distance sensors measure local height surface. The curves show maxima only for odd multiples fundamental frequency $$f_0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>f</mml:mi> <mml:mn>0</mml:mn> </mml:msub> </mml:math> . We explained this behavior using simple...

We study thin film instabilities in liquid films with deformable surface using the lubrication theory. An externally applied vertical temperature gradient may give cause to an instability (Marangoni instability) of flat motionless film. Contrary earlier work where mostly pure fluids were discussed, focus present paper lays on mixtures two completely miscible liquids. show that normally found monotonic long-wave turn into oscillatory one if components have a different tension and Soret...

The differentially heated rotating annulus is a laboratory experiment historically designed for modelling large-scale features of the mid-latitude atmosphere. In present study, we investigate modified version classic baroclinic in which juxtaposition convective and motionless stratified layers created by introducing vertical salt stratification. thermal motions are suppressed central region at mid-depth tank, therefore double-diffusive convection rolls can develop only thin located top...

Atmospheric westerly jet streams are driven by temperature differences between low and high latitudes the rotation of Earth. Meandering propagating Rossby waves responsible for variable weather in mid-latitudes. Moreover, extreme events such as heat cold spells part stream dynamics. For many years, a simple analog form simplified laboratory experiment, differentially heated rotating annulus, has provided insight into dynamics meandering stream. In present study, probability density...

In a remarkable paper, Cox and Mortell (1986) (A.A. Cox, M.P. 1986. J. Fluid Mech. 162, pp. 99-116) showed that for an oscillating water tank, the evolution of small-amplitude, long-wavelength, resonantly forced waves follow Korteweg–de Vries (fKdV) equation. The solutions this model agree well with experimental results by Chester Bones (1968) (W. J.A. 1968. Proc. Roy. Soc. A, 306, 23 (Part II)). We compare fKdV number channel flows different geometry have been studied experimentally...

Abstract

Abstract Pronounced global cooling around the Eocene–Oligocene transition (EOT) was a pivotal event in Earth’s climate history, controversially associated with opening of Drake Passage. Using physical laboratory model we revisit fluid dynamics this marked reorganization ocean circulation. Here show, seemingly contradicting paleoclimate records, that our experiments pathway yields higher values mean water surface temperature than “closed” configuration. This mismatch points to importance role...

A thermal variable variance Preisach-Neel model was developed. The effect of the applied field and interaction studied in zero cooled simulated processes using different expressions for barrier expression ways Preisach distribution modification due to effects. advantages disadvantages each variant were investigated.

A water-filled differentially heated rotating annulus with initially prepared stable vertical salinity profiles is studied in the laboratory. Based on two-dimensional horizontal particle image velocimetry (PIV) data, and infrared camera visualizations, we describe appearance characteristics of baroclinic instability this original configuration. First, show that when profile linear confined between two non stratified layers at top bottom, only separate shallow fluid can be destabilized. These...

Recently, we systematically derived a system of two coupled conservation equations governing thin liquid layer with deformable surface composed completely miscible components [Phys. Fluids 22, 104102 (2010)]. One equation describes the location free and second one evolution mean concentration. This lubrication model was investigated previously in linearized form. The study is now extended to fully nonlinear case films binary mixture (in horizontal spatial dimensions) without heat transport....