A global ocean circulation model is formulated in terms of the “residual mean” and used to study eddy–mean flow interaction. Adjoint techniques are used to compute the three-dimensional eddy stress field that minimizes the departure of the coarse-resolution model from climatological observations of temperature. The resulting 3D maps of eddy stress and residual-mean circulation yield a wealth of...

Abstract In this paper, to improve the combustion characteristics and working performance of solid fuel ramjet, a ramjet with gas generator is proposed. Based on k − ω SST Eddy-Dissipation equations, turbulent model established, internal flow field as well regression rate, species, were numerically analyzed. The results show that temperature rate increased. When airflow 0.4kg/s, increase will l...

A refined two-term helical subgrid-scale (SGS) stress model with respect to that suggested by Li et al. [Phys. Rev. E 74, 026310 (2006)] is designed for large-eddy simulation (LES) of helical turbulence. The model coefficients in the new model are verified a priori to be scale invariant in inertial range, which proves that our model is local in scale. A dynamic method based on minimizing the re...

For the purpose of studying the spectral properties of energy transfer between large and small scales in high-Reynolds-number turbulence, we measure the longitudinal subgrid-scale (SGS) dissipation spectrum, defined as the co-spectrum of the SGS stress and filtered strain-rate tensors. An array of four closely spaced X-wire probes enables us to approximate a two-dimensional box filter by averag...

Synoptic eddy–mean flow interaction has been recognized as one of the key sources for extratropical lowfrequency variability. In this paper, the underlying dynamics of this interaction are examined from the perspective of a synoptic eddy-induced dynamic instability. To delineate this instability, a barotropic model is used that is linearized with respect to a stochastic basic flow prescribed wi...

The primary focus of this research is to use large-eddy simulation (LES) and large-wave simulation (LWS) to obtain improved physical understanding of wind-wave-ocean interactions, based on which we aim to develop effective models of wind input and whitecapping dissipation for phase-resolving, nonlinear wave-field simulation at large scales. Our ultimate goal is to establish a numerical capabili...

This paper presents the use of a dynamically adaptive mesh refinement strategy for the simulations of shock-driven turbulent mixing. Large-eddy simulations are necessary due the high Reynolds number turbulent regime. In this approach, the large scales are simulated directly and small scales at which the viscous dissipation occurs are modeled. A low-numerical centered finite-difference scheme is...

Timely alerting of turbulence is crucial to assuring flight safety. In the existing Windshear and Turbulence Warning System (WTWS) operated by the Hong Kong Observatory (HKO), turbulence along flight paths, which is quantified in terms of the cube root of Eddy Dissipation Rate (edr 1/3 ) following international aviation practice, is estimated from the data of surface anemometers in the vicinity...