Flow characteristics are presented of simulation results of plane impinging jets at high nozzle-plate distances, with two k-ω based hybrid RANS/LES (Reynolds Averaged Navier–Stokes/Large–Eddy Simulation) models and a k-ω RANS model. The first hybrid RANS/LES model is obtained by substitution of the turbulent length scale by the local grid size in the destruction term of the turbulent kinetic en...

Large eddy simulation of turbulent flow is given a natural setting in the DSC framework of computational fluid dynamics. Periodic cellular coarsegraining prevents the nodal flow from piling up and preserves its large patterns. The coarsening operations are consistent with the near-field interaction principle of DSC and therefore uncomplicated at boundaries. Numerical examples validate the appro...

A methodology is proposed for the assessment of error dynamics in large-eddy simulations. It is demonstrated that the optimization of model parameters with respect to one flow property can be obtained at the expense of the accuracy with which other flow properties are predicted. Therefore, an approach is introduced which allows to assess the total errors based on various flow properties simulta...

In this three-part study, a linear closure has been developed for the synoptic eddy and low-frequency flow (SELF) interaction and demonstrated that internal dynamics plays an important role in generating the leading low-frequency modes in the extratropical circulation anomalies during cold seasons. In Part III, a new linearized primitive equation system is first derived for time-mean flow anoma...

oil and gas transmission pipelines are critical items of infrastructure in providing energy sources to regions and countries. steel pipes are commonly used which can be subject to both internal and external corrosion. this paper presents an advanced nondestructive inspection technique for detection of oil-gas pipeline corrosion defect. the pulsed eddy current (pec) method has been successfully ...

The diffusive effect on barotropic models of mesoscale eddies is addressed, using the Melnikov method from dynamical systems. Simple geometric criteria are obtained, which identify whether a given eddy grows or drains out, under a diffusive (and forcing) perturbation on a potential vorticity conserving flow. Qualitatively, the following are shown to be features conducive to eddy growth (and, th...

Detailed information about the flow field pattern is highly important in accurately predicting particle deposition sites in the human airway. Flow in the upper airway during heavy breathing can have a Reynolds number as high as 9300, and therefore presents turbulent features. Although turbulence is believed to have an important effect on the airflow and other transport processes in the bronchia...

A linear response function (LRF) determines the mean-response of a nonlinear climate system to weak imposed forcings, and an eddy flux matrix (EFM) determines the eddy momentum and heat flux responses to mean-flow changes. Neither LRF nor EFM can be calculated from first principles due to the lack of a complete theory for turbulent eddies. Here the LRF and EFM for an idealized dry atmosphere ar...

جریان­های غلیظ به طور کلی به دو دسته جریان­های غلیظ پایدار(مانند جریان غلیظ نمکی) و جریان­های غلیظ ناپایدار(مانند جریان غلیظ رسوبی یا جریان کدر) تقسیم­بندی می­شوند. رخداد این گونه از جریان­ها در مخازن سدها باعث انتقال رسوبات به نزدیکی بدنه سد و ایجاد خطر برای تاسیسات و سازه­های در نظر گرفته شده برای تامین اهداف سد می­شود. یکی از این روش­ها، خارج کردن رسوبات حاصل از جریان­های سیلابی، با ...

Zonostrophic instability leads to the spontaneous emergence of zonal jets on a b plane from a jetless basicstate flow that is damped by bottom drag and driven by a random body force. Decomposing the barotropic vorticity equation into the zonal mean and eddy equations, and neglecting the eddy–eddy interactions, defines the quasilinear (QL) system. Numerical solution of the QL system shows zonal ...