نتایج جستجو برای: turbulence intensity

تعداد نتایج: 216562  

2010
R. Mathis

A new view of the scaling of the streamwise turbulence intensity profile is proposed for the zero pressure gradient turbulent boundary layer. The method is based on the scale decomposed streamwise velocity component, separated into a smalland a large-scale contribution using a wavelength pass-filter. This enables us to understand how large and small scale motions affect the streamwise turbulenc...

2017
Xingquan Wu Guosheng Xu Baonian Wan Jens Juul Rasmussen Volker Naulin Anders Henry Nielsen

To understand the connection between the dynamics of microscopic turbulence and the macroscale power scaling in the L–I–H transition in magnetically confined plasmas, a new time-dependent, one-dimensional (in radius) model has been developed. The model investigates the radial force balance equation at the edge region of the plasma and applies the quenching effect of turbulence via the E × B flo...

2009
Siming Liu Lyndsay Fletcher

Most theoretical investigations of particle acceleration during solar flares cannot be applied to observations for detailed study of the time evolution. We propose a phenomenological model for turbulence evolution and stochastic particle acceleration that links observations to the energy release and particle acceleration through two coefficients characterising particle interactions with turbule...

Journal: :Optics express 2013
Weilin Hou Ewa Jarosz Sarah Woods Wesley Goode Alan Weidemann

Acoustical and optical signal transmission underwater is of vital interest for both civilian and military applications. The range and signal to noise during the transmission, as a function of system and water optical properties, in terms of absorption and scattering, determines the effectiveness of deployed electro-optical (EO) technology. The impacts from turbulence have been demonstrated to a...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2006
Steve Zamek Yitzhak Yitzhaky

In remote sensing, atmospheric turbulence and aerosols usually limit the image quality. For many practical cases, turbulence is shown to be dominant, especially for horizontal close-to-earth imaging in hot environments. In a horizontal long-range imaging, it is usually impractical to calculate path-averaged refractive index structure constant C(2)(n) (which characterizes the turbulence strength...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده مهندسی 1388

هدف از انجام این پایان¬نامه استخراج توابع ویژه تجربی از داده¬های آزمایشگاهی با روش تجزیه متعامد سره (pod) و استفاده از این توابع برای حل معادلات جریان می¬باشد. مدهای اول حاصل از به¬کاربردن روش تجزیه متعامد سره بیانگر ساختارهای منسجم درون سیال می¬باشند. ساختارهای منسجم به طور طبیعی در اکثر جریان¬های متلاطم حضور دارند و به عنوان ساختارهایی که دینامیک اصلی جریان را کنترل می¬کنند، شناخته می¬شوند. د...

2005
R. Mei

Recent developments concerning the unsteady dynamic forces on a spherical particle at finite Reynolds number are reviewed for solid particles and clean micro-bubble. A particle frequency response function and an energy transfer function are derived for a solid particle or a contaminated micro-bubble in gas or liquid flow. A simple, unified method for estimating the cut-off frequency, or cut-off...

2012
S. Wang

This discussion paper is/has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP if available. Abstract Unusually large wind shears across the inversion in the stratocumulus-topped marine boundary layer (MBL) were frequently observed during VOCALS-REx. To investigate the impact of wind shear on the MBL turbulence struct...

2007
Itzhak Goldman

The spatial power spectrum of the HI 21 cm intensity in the Small Magellanic Cloud (Stanimirovic et al.1999) is a power law over scales as large as those of the SMC itself. It was interpreted as due to turbulence by Goldman (2000) and by Stanimirovic & Lazarian (2001). The question is whether the power spectrum is indeed the result of a dynamical turbulence or is merely the result of a structur...

Journal: :IET Communications 2013
Duy A. Luong Truong C. Thang Anh T. Pham

In this study, the authors theoretically study the performance of direct-detection free-space optical communication systems using binary phase-shift keying subcarrier-intensity modulation and avalanche photodiode (APD). The system biterror rate and channel capacity are theoretically derived in cases of log-normal and gamma-gamma channel models for weakto-moderate and moderate-to-strong atmosphe...

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