Abstract In the traditional hybrid RANS/LES approaches for simulation of wall-bounded fluid turbulence, such as detached-eddy (DES), whole flow domain is divided into an inner layer and outer layer. Typically Reynolds-averaged Navier–Stokes (RANS) equations are used layer, while large-eddy (LES) The transition from inner-layer solution to outer-layer often problematic due lack small-scale dynamics in RANS region. this paper, we propose simulate by enforcing a Reynolds-stress constraint on...

There is considerable interest in hydrodynamic instabilities dead zones of protoplanetary disks as a mechanism for driving angular momentum transport and source particle-trapping vortices to mix chondrules incubate planetesimal formation. We present simulations with pseudo-spectral anelastic code the compressible Athena, showing that stably stratified flows shearing, rotating box are violently unstable produce space-filling, sustained turbulence dominated by large Rossby numbers order...

A previously unknown instability creates space-filling lattices of 3D vortices in linearly stable, rotating, stratified shear flows. The starts from an easily excited critical layer. layer intensifies by drawing energy the background and rolls up into that excite new layers vortices. self-similarly replicate to create turbulent persist for all time. This self-replication occurs Couette flows dead zones protoplanetary disks where it can destabilize Keplerian

Abstract Previous studies demonstrate that the Madden‐Julian Oscillation (MJO) modulates tropical cyclone (TC) activity over various locations worldwide. Since TCs are associated with anomalous large‐scale circulations, they can influence development of MJO. However, impact TC on MJO has not been thoroughly examined. This study investigates TC‐associated processes based analysis a case observed during Dynamics field campaign. During suppressed phase before December 2011 initiation, two were...

ABSTRACT In Zombie Vortex Instability (ZVI), perturbations excite critical layers in stratified, rotating shear flow (as protoplanetary disks (PPDs)), causing them to generate vortex layers, which roll up into anticyclonic zombie vortices and cyclonic sheets. The process is self-sustaining as perturb new spawning a next generation of vortices. Here, we focus on two issues: the minimum threshold that trigger generation, properties late-time turbulence large small scales. parameter determines...

Abstract Atmospheric cold pools are frequently observed during the Madden‐Julian Oscillation events and play an important role in development organization of large‐scale convection. They generally associated with heavy precipitation strong winds, inducing large air‐sea fluxes significant sea surface temperature (SST) fluctuations. This study provides a first detailed investigation upper ocean response to Oscillation, based on analysis situ data collected Dynamics (DYNAMO) field campaign...

Abstract Deep cycle turbulence (DCT) is a diurnally oscillating that penetrates into stratified shear layer below the surface mixed layer, which often observed in eastern Pacific and Atlantic above Equatorial Undercurrent (EUC). Here we present simulation of DCT by global ocean general circulation model (OGCM) for first time. As k ‐ ε vertical mixing scheme used OGCM, structure based on situ microstructure measurements can be explicitly demonstrated. The simulated found all equatorial...

Abstract Substantial (∼2°C) basin averaged sea surface temperature (SST) cooling in the Banda Sea occurred less than a 14‐day period during 2015 boreal winter Madden‐Julian Oscillation (MJO). Such rapid and large associated with MJO has not been reported at least last two decades. Processes that control substantial event are examined using high‐resolution ocean reanalysis one‐dimensional (1‐D) model simulations. Previous studies suggest MJO‐induced SST variability is primarily controlled by...

The Zombie Vortex Instability (ZVI) occurs in the dead zones of protoplanetary disks (PPDs) where perturbations excite baroclinic critical layers, generating "zombie" vortices and turbulence. In this work, we investigate ZVI with nonuniform vertical stratification; while is triggered stratified regions away from midplane, subsequent turbulence propagates into fills midplane. alters background Keplerian shear flow, creating a steady-state zonal flow. Intermittency observed, flow cycles...

Abstract Given the increasing attention in forecasting weather and climate on subseasonal time scale recent years, National Oceanic Atmospheric Administration (NOAA) announced to support Climate Process Teams (CPTs) which aim improve Madden‐Julian Oscillation (MJO) prediction by NOAA’s global models. Our team supported this CPT program focuses primarily improvement of upper ocean mixing parameterization air‐sea fluxes NOAA Forecast System (CFS). Major includes increase vertical resolution...

We show that the “dead” zone of a protoplanetary disk fills with robust 3D vortices from purely hydrodynamic instability. This new instability is not linear and requires weak finite-amplitude initial perturbation. The was seen previously either due to lack numerical spatial resolution, or because many previous simulations ignored vertical gravity had flows constant density. Our family previously-unknown critical layers form in rotating, shearing, vertically stratified like those disks....