The unstable flow with rotating-stall-like (RS) effects in a rotor-cascade of an axial compressor was numerically investigated. The RS was captured with the reduction in mass flow rate and increasing of exit static pressure with respect to design operating condition of the single rotor. The oscillatory velocity traces during the stall propagation showed that the RS vortices repeat periodically,...

Coastal upwellings, due to offshore Ekman transport, are more energetic at the western boundaries of oceans, where they intensified by incoming Rossby waves, than eastern boundaries. Western boundary upwellings often accompanied a local vortex field. The instability developed upwelling front and its interaction with an external field is studied here three-dimensional numerical model hydrostatic...

We present observations at near-infrared wavelengths (1–5 lm) of Jupiter’s north polar region and Northern Red Oval (NN-LRS-1). The observations were taken with the near-infrared camera NIRC2 coupled to the adaptive optics system on the 10-mW.M. Keck Telescope on UT 21 August 2010. At 5-lm Jupiter’s disk reveals considerable structure, including small bright rings which appear to surround all s...

[1] Global sea surface height anomaly signals from the TOPEX/Poseidon satellite altimeter from 1992 to 2000 are filtered into several spectral bands. These bands include propagating (Rossby, Kelvin, and tropical instability waves) and nonpropagating (annual and interannual basin-scale variability and eddies) signals. These signals are decomposed through a series of finite impulse response band-...

We investigate the nonlinear evolution of pairs three-dimensional, equal-sized and opposite-signed vortices at finite Froude Rossby numbers. The two may be offset in vertical direction. initial conditions stem from relative equilibria obtained numerically quasi-geostrophic regime, for vanishing first address linear stability vortices, show that all offsets, are sensitive to an instability when ...

The emission of inertia-gravity waves (IGWs) from an exact geostrophic vortex in a rotating and stratified fluid is investigated by three-dimensional numerical modeling. An initially balanced inevitably generates IGWs with spiral patterns within short transient time period through instability mechanism. This result reinforces the nonexistence exactly invariant slow manifolds. direction rotation...

The tropical intraseasonal oscillation (ISO) exhibits pronounced seasonality. The boreal summer ISO is more complex than its winter counterpart due to the coexistence of equatorial eastward, off-equatorial westward, and northward propagating, low-frequency modes and their interactions. Based on observational evidence and results obtained from numerical experiments, a mechanism is proposed for t...

[1] Argo float data (subsurface tracks and temperature profiles collected from March 2004 through May 2005) are used to detect signatures of long Rossby waves in the velocity of the currents at 1000-m depth and temperature, between the ocean surface and 950 m, in the zonal band of 4 N–24 N in the tropical North Atlantic. Different types of long Rossby waves (with the characteristic scales betwe...

Rossby waves are a principal form of atmospheric communication between disparate parts of the climate system. These planetary waves are typically excited by diabatic or orographic forcing and can be subject to considerable downstream modification. Because of differences in wave properties, including vertical structure, phase speed, and group velocity, Rossby waves exhibit a wide range of behavi...

A technique is described to observe Rossby waves in the oceans using altimeter data, which makes use of longitude/time diagrams of sea surface height anomalies at a given latitude, relying on the zonal propagation of those waves. By means of the Fast Fourier and Radon transforms of the longitude/time diagrams it is possible to locate the spectral components corresponding to wave propagation and...