نتایج جستجو برای: tke profile

تعداد نتایج: 221100  

2012
Michel A. J. de Nijs Julie D. Pietrzak

Measurements of turbulent fluctuations of horizontal and vertical components of velocity, salinity and suspended particulate matter are presented. Turbulent Prandtl numbers are found to increase with stratification and to become larger than 1. Consequently, the vertical turbulent mass transport is suppressed by buoyancy forces, before the turbulent kinetic energy (TKE) and vertical turbulent mo...

Journal: :Magnetic resonance in medicine 2017
Magnus Ziegler Jonas Lantz Tino Ebbers Petter Dyverfeldt

PURPOSE To explore the use of MR-estimated turbulence quantities for the assessment of turbulent flow effects on the vessel wall. METHODS Numerical velocity data for two patient-derived models was obtained using computational fluid dynamics (CFD) for two physiological flow rates. The four-dimensional (4D) Flow MRI measurements were simulated at three different spatial resolutions and used to ...

Journal: :محیط شناسی 0
خسرو اشرفی استادیار گروه مهندسی عمران محیط زیست دانشکدۀ محیط زیست دانشگاه تهران مجید شفیع پور مطلق استادیار گروه مهندسی عمران محیط زیست دانشکدۀ محیط زیست دانشگاه تهران حدیث عباس زاده امیردهی کارشناس ارشد مهندسی عمران محیط زیست دانشکدۀ محیط زیست دانشگاه تهران

introduction air pollution has harmful effect on human health and the environment. accordingly, considerable effort has been put to analyze the air pollutants. one important issue is the spatial distribution of these pollutants. dispersion of the pollutants released from sources on the ground is mostly driven by the planetary boundary layer where turbulent flow causes mixing of the content of t...

ژورنال: دریا فنون 2019

در این مقاله تاثیر تبخیر بر لایه آمیخته اقیانوسی در حضور یا عدم حضور گردش لانگمویر و شکست موج با استفاه از شبیه سازی پیچک بزرگ بررسی و در تعریف شبیه سازی، از پارامترهای نزدیک به مونسون تابستانه دریای عربی استفاده شد. شبیه سازی برای 5/33 ساعت انجام و از خروجی های 5/9 ساعت ابتدایی صرف نظر شد و پارامترهای مختلف در یک بازه ی 24 ساعته مورد بررسی قرار گرفتند. در حضور تبخیر و واداشت باد و عدم حضور گرد...

2015
Tyler Fricker James B. Elsner Inés Álvarez

Tornadoes can cause catastrophic destruction. Here total kinetic energy (TKE) as a metric of destruction is computed from the fraction of the tornado path experiencing various damage levels and a characteristic wind speed for each level. The fraction of the path is obtained from a model developed for the Nuclear Regulatory Commission that combines theory with empirical data. TKE is validated as...

Journal: :Magnetic resonance imaging 2016
Petter Dyverfeldt Tino Ebbers

Quantifying turbulence velocity fluctuation is important because it indicates the fluid energy dissipation of the blood flow, which is closely related to the pressure drop along the blood vessel. This study aims to evaluate the effects of scan parameters and the target vessel size of 4D phase-contrast (PC)-MRI on quantification of turbulent kinetic energy (TKE). Comprehensive 4D PC-MRI measurem...

2013
Christian Geißler Karin Nadrowski Peter Kühn Martin Baruffol Helge Bruelheide Bernhard Schmid Thomas Scholten

Throughfall kinetic energy (TKE) plays an important role in soil erosion in forests. We studied TKE as a function of biodiversity, functional diversity as well as structural stand variables in a secondary subtropical broad-leaved forest in the Gutianshan National Nature Reserve (GNNR) in south-east China, a biodiversity hotspot in the northern hemisphere with more than 250 woody species present...

Journal: :Weather and Forecasting 2022

Abstract Better representation of the planetary boundary layer (PBL) in numerical models is one keys to improving forecasts TC structure and intensity, including rapid intensification. To meet this goal, our recent work has used observations improve eddy-diffusivity mass flux with prognostic turbulent kinetic energy (EDMF-TKE) PBL scheme Hurricane Analysis Forecast System (HAFS). This study bui...

2013
Petter Dyverfeldt Michael D Hope Elaine E Tseng David Saloner

Background Pressure loss estimation based on the simplified Bernoulli equation frequently misclassifies the severity of aortic stenosis. Consequently, several investigators have on the basis of fluid dynamics theory derived pressure loss indices aimed at improving the clinical approach to pressure estimation [1-3]. However, CMR may offer a stronger alternative. The primary cause of pressure los...

2016

“In SOSAA, the horizontal wind velocity (u and v), temperature (T ), specific humidity (qv), turbulent kinetic energy (TKE) and the specific dissipation of TKE (ω) are computed every time step (10 s) by prognostic equations. In order to represent the local to synoptic scale effects, u, v, T and qv near and within the canopy are nudged to local measurement data at SMEAR II station with a nudging...

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