Testing steady and transient velocity scalings in a silo

2018 ◽  
Vol 29 (2) ◽  
pp. 310-318 ◽  
Author(s):  
L.A. Fullard ◽  
C.E. Davies ◽  
A.C. Neather ◽  
E.C.P. Breard ◽  
A.J.R. Godfrey ◽  
...  
Keyword(s):  
Transient Velocity

Prediction of Slamming Loads on Catamaran Wetdeck Using CFD

2015 ◽  
Author(s):  
Ahmed Swidan ◽  
Giles Thomas ◽  
Dev Ranmuthugala ◽  
Irene Penesis ◽  
Walid Amin ◽  
...  
Keyword(s):  
Model Simulation ◽  
Three Dimensional ◽  
Grid Method ◽  
Computationally Efficient ◽  
Overset Grid ◽  
Force Magnitude ◽  
Overset Grid Method ◽  
Drop Tests ◽  
Transient Velocity ◽  
Transient Velocity Profile

Wetdeck slamming is one of the principal hydrodynamic loads acting on catamarans. CFD techniques are shown to successfully characterise wetdeck slamming loads, as validated through a series of controlled-speed drop tests on a three-dimensional catamaran hullform model. Simulation of water entry at constant speed by applying a fixed grid method was found to be more computationally efficient than applying an overset grid. However, the overset grid method for implementing the exact transient velocity profile resulted in better prediction of slam force magnitude. In addition the splitting force concurrent with wetdeck slam event was quantified to be 21% of the vertical slamming force.

COMPARISON OF TRANSIENT BALLISTIC ELECTRON TRANSPORT IN BULK WURTZITE PHASE 6H-SiC and GaN

2008 ◽  
Vol 22 (30) ◽  
pp. 5289-5297 ◽  
Author(s):  
H. ARABSHAHI
Keyword(s):  
Conduction Band ◽  
Drift Velocity ◽  
Velocity Ratio ◽  
Ballistic Transport ◽  
Energy Separation ◽  
Wurtzite Phase ◽  
Velocity Overshoot ◽  
Ballistic Electron ◽  
Ballistic Electron Transport ◽  
Transient Velocity

An ensemble Monte Carlo simulation is used to compare bulk electron ballistic transport in 6H - SiC and GaN materials. Electronic states within the conduction band valleys at Γ1, U, M, Γ3, and K are represented by nonparabolic ellipsoidal valleys centered on important symmetry points of the Brillouin zone. The large optical phonon energy (~120 meV) and the large intervalley energy separation between the Γ and satellite conduction band valleys suggest an increasing role for ballistic electron effects in 6H - SiC , especially when compared with most III-V semiconductors such as GaAs . Transient velocity overshoot has been simulated, with the sudden application of fields up to ~5×107 Vm -1, appropriate to the gate-drain fields expected within an operational field effect transistor. A peak-saturation drift velocity ratio of 2:1 is predicted for 6H - SiC material while that for GaN is 4:1. The electron drift velocity relaxes to the saturation value of ~2×105 ms -1 within 3 ps, for both crystal structures. The transient velocity overshoot characteristics are in fair agreement with other recent calculations.

Factorial Analysis on the 2-D Transient Solid Velocity in Fluidized Bed Combustor

2003 ◽  
Author(s):  
Seong W. Lee ◽  
Yun Liu
Keyword(s):  
Fluidized Bed ◽  
Particle Velocity ◽  
Design Method ◽  
Factorial Analysis ◽  
Cold Model ◽  
Experimental Conditions ◽  
Image Velocimetry ◽  
Transient Velocity ◽  
Particle Velocities ◽  
Fluidized Bed Combustor

The transient solid velocity analysis in fluidized bed combustor (FBC) freeboard has been critical in the past two decades (Haidin et al 1998). The FBC cold model (6-in ID) was designed and fabricated. The solid transient velocity in FBC freeboard was measured and analyzed with the assistance of the advanced instrumentation. The laser-based Particle Image Velocimetry (PIV) was applied to the FBC cold model to visualize the transient solid velocity. A series of transient particle velocity profiles were generated for factorial analysis. In each profile, the particle velocity vectors for 100 position points were in the format of Vx and Vy. Analysis of Variance (ANOVA) was used to determine the significant factors that affect the transient particle velocities, time, and position coordinates. Then, the 1010factorial design method was used to develop a specific empirical model of transient particle velocity in FBC freeboard which was in the shape of Vx = f1(t, x, y), and Vy = f2(t, x, y). This unique factorial analysis method was proved to be very effective and practical to evaluate the experimental conditions and analyze the experimental results in FBC systems.

scholarly journals Corrigendum

2018 ◽  
Vol 232 (2) ◽  
pp. NP1-NP1
Keyword(s):  
Boundary Conditions ◽  
Peer Review ◽  
Clinical Data ◽  
Human Error ◽  
Transient Flow ◽  
Rabbit Aorta ◽  
Original Version ◽  
Subject Specific ◽  
Transient Velocity ◽  
Specific Rabbit

McElroy M and Keshmiri A, Impact of using conventional inlet/outlet boundary conditions on haemodynamic metrics in a subject-specific rabbit aorta, Proc IMechE, Part H: Journal of Engineering in Medicine, first published on March 25, 2017, DOI: 10.1177/0954411917699237 Following OnlineFirst publication of the article, the authors informed SAGE of an error in the transient velocity inlet profile which had been defined inaccurately due to a human error in the interpretation of clinical data in the literature. As a result of this error in boundary conditions, some of the results of transient flow computations were incorrect. A watermarked version of the first publication of the article (as first published on March 25, 2017) is attached for reference in the PDF version of this corrigendum. The authors have revised and corrected their article. The revised version of the article has been accepted following peer review and replaces the article first published on March 25, 2017. Date received: 8 August 2017; accepted: 30 November 2017 (Revised version) Date received: 29 March 2016; accepted: 21 February 2017 (Original version) The correct and citable version of the article is accessible at the following DOI: 10.1177/0954411917699237

A comparison of transient velocity overshoot in Si and GaAs structures

1992 ◽  
Vol 7 (3B) ◽  
pp. B390-B393 ◽  
Author(s):  
D T Hughes ◽  
R A Abram ◽  
R W Kelsall ◽  
A J Holden
Keyword(s):  
Velocity Overshoot ◽  
Transient Velocity

scholarly journals A Study of Simultaneous 2-D Measurement for Transient Velocity and Temperature Using Two Color Lasers

2002 ◽  
Vol 22 (4) ◽  
pp. 28-35
Author(s):  
Ichiro NAKANE ◽  
Akira NARUMI ◽  
Kentaro FUKUDA ◽  
Akihiko ITO
Keyword(s):  
Transient Velocity
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