**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**2708

# Search results for: Velocity Modeling.

##### 2708 Velocity Filter Banks using 3-D FFT

**Authors:**
G. Koukiou,
V. Anastassopoulos

**Abstract:**

**Keywords:**
Velocity filters,
filter banks,
3-D FFT.

##### 2707 CFD Simulation of Condensing Vapor Bubble using VOF Model

**Authors:**
Seong-Su Jeon,
Seong-Jin Kim,
Goon-Cherl Park

**Abstract:**

In this study, direct numerical simulation for the bubble condensation in the subcooled boiling flow was performed. The main goal was to develop the CFD modeling for the bubble condensation and to evaluate the accuracy of the VOF model with the developed CFD modeling. CFD modeling for the bubble condensation was developed by modeling the source terms in the governing equations of VOF model using UDF. In the modeling, the amount of condensation was determined using the interfacial heat transfer coefficient obtained from the bubble velocity, liquid temperature and bubble diameter every time step. To evaluate the VOF model using the CFD modeling for the bubble condensation, CFD simulation results were compared with SNU experimental results such as bubble volume and shape, interfacial area, bubble diameter and bubble velocity. Simulation results predicted well the behavior of the actual condensing bubble. Therefore, it can be concluded that the VOF model using the CFD modeling for the bubble condensation will be a useful computational fluid dynamics tool for analyzing the behavior of the condensing bubble in a wide range of the subcooled boiling flow.

**Keywords:**
Bubble condensation,
CFD modeling,
Subcooled boiling flow,
VOF model.

##### 2706 Real Time Monitoring of Long Slender Shaft by Distributed-Lumped Modeling Techniques

**Authors:**
Sina Babadi,
K. M. Ebrahimi

**Abstract:**

**Keywords:**
Distributed Lumped modeling,
Lumped modeling,
Drill string,
Angular Velocity,
Torque.

##### 2705 Handwriting Velocity Modeling by Artificial Neural Networks

**Authors:**
Mohamed Aymen Slim,
Afef Abdelkrim,
Mohamed Benrejeb

**Abstract:**

The handwriting is a physical demonstration of a complex cognitive process learnt by man since his childhood. People with disabilities or suffering from various neurological diseases are facing so many difficulties resulting from problems located at the muscle stimuli (EMG) or signals from the brain (EEG) and which arise at the stage of writing. The handwriting velocity of the same writer or different writers varies according to different criteria: age, attitude, mood, writing surface, etc. Therefore, it is interesting to reconstruct an experimental basis records taking, as primary reference, the writing speed for different writers which would allow studying the global system during handwriting process. This paper deals with a new approach of the handwriting system modeling based on the velocity criterion through the concepts of artificial neural networks, precisely the Radial Basis Functions (RBF) neural networks. The obtained simulation results show a satisfactory agreement between responses of the developed neural model and the experimental data for various letters and forms then the efficiency of the proposed approaches.

**Keywords:**
ElectroMyoGraphic (EMG) signals,
Experimental
approach,
Handwriting process,
Radial Basis Functions (RBF) neural
networks,
Velocity Modeling.

##### 2704 Kirchhoff’s Depth Migration over Heterogeneous Velocity Models with Ray Tracing Modeling Approach

**Authors:**
Alok Kumar Routa,
Priya Ranjan Mohanty

**Abstract:**

Complex seismic signatures are generated due to the complexity of the subsurface which is difficult to interpret. In the present study, an attempt has been made to model the complex subsurface using the Ray tracing modeling technique. Add to this, for the imaging of these geological features, Kirchhoff’s prestack depth migration is applied over the synthetic common shot gather dataset. It is found that the Kirchhoff’s migration technique in addition with the Ray tracing modeling concept has the flexibility towards the imaging of various complex geology which gives satisfactory results with proper delineation of the reflectors at their respective true depth position. The entire work has been carried out under the MATLAB environment.

**Keywords:**
Kirchhoff’s migration,
Prestack depth migration,
Ray tracing modeling,
Velocity model.

##### 2703 Effects of Injection Velocity and Entrance Airflow Velocity on Droplets Sizing in a Duct

**Authors:**
M. M. Doustdar ,
M. Mojtahedpoor

**Abstract:**

**Keywords:**
Ramjet,
droplet sizing,
injection velocity,
air flow
velocity,
efficient mass fraction.

##### 2702 Kinetic Theory Based CFD Modeling of Particulate Flows in Horizontal Pipes

**Authors:**
Pandaba Patro,
Brundaban Patro

**Abstract:**

The numerical simulation of fully developed gas–solid flow in a horizontal pipe is done using the eulerian-eulerian approach, also known as two fluids modeling as both phases are treated as continuum and inter-penetrating continua. The solid phase stresses are modeled using kinetic theory of granular flow (KTGF). The computed results for velocity profiles and pressure drop are compared with the experimental data. We observe that the convection and diffusion terms in the granular temperature cannot be neglected in gas solid flow simulation along a horizontal pipe. The particle-wall collision and lift also play important role in eulerian modeling. We also investigated the effect of flow parameters like gas velocity, particle properties and particle loading on pressure drop prediction in different pipe diameters. Pressure drop increases with gas velocity and particle loading. The gas velocity has the same effect ((proportional toU2 ) as single phase flow on pressure drop prediction. With respect to particle diameter, pressure drop first increases, reaches a peak and then decreases. The peak is a strong function of pipe bore.

**Keywords:**
CFD,
Eulerian modeling,
gas solid flow,
KTGF.

##### 2701 Estimation of Shock Velocity and Pressure of Detonations and Finding Their Flow Parameters

**Authors:**
Mahmoud Zarrini,
R. N. Pralhad

**Abstract:**

In this paper, mathematical modeling of detonation in the ground is studied. Estimation of flow parameters such as velocity, maximum velocity, acceleration, maximum acceleration, shock pressure as a result of an explosion in the ground have been computed in an appropriate dynamic model approach. The variation of these parameters with the diameter of detonation place (L), density of earth or stone (¤ü), time decay of detonation (T), peak pressure (Pm), and time (t) have been analyzed. The model has been developed from the concept of underwater explosions [Refs. [1]-[3]] with appropriate changes to the present model requirements.

**Keywords:**
Shock velocity,
detonation,
shock acceleration,
shock pressure.

##### 2700 Measurements of Radial Velocity in Fixed Fluidized Bed for Fischer-Tropsch Synthesis Using LDV

**Authors:**
Xiaolai Zhang,
Haitao Zhang,
Qiwen Sun,
Weixin Qian,
Weiyong Ying

**Abstract:**

**Keywords:**
LDV,
fixed fluidized bed,
velocity,
Fischer-Tropsch
synthesis.

##### 2699 Study of Flow Behavior of Aqueous Solution of Rhodamine B in Annular Reactor Using Computational Fluid Dynamics

**Authors:**
Jatinder Kumar,
Ajay Bansal

**Abstract:**

The present study deals with the modeling and simulation of flow through an annular reactor at different hydrodynamic conditions using computational fluid dynamics (CFD) to investigate the flow behavior. CFD modeling was utilized to predict velocity distribution and average velocity in the annular geometry. The results of CFD simulations were compared with the mathematically derived equations and already developed correlations for validation purposes. CFD modeling was found suitable for predicting the flow characteristics in annular geometry under laminar flow conditions. It was observed that CFD also provides local values of the parameters of interest in addition to the average values for the simulated geometry.

**Keywords:**
Annular reactor,
computational fluid dynamics
(CFD),
hydrodynamics,
Rhodamine B

##### 2698 Velocity Distribution in Open Channels with Sand: An Experimental Study

**Authors:**
E. Keramaris

**Abstract:**

In this study, laboratory experiments in open channel flows over a sand bed were conducted. A porous bed (sand bed) with porosity of ε=0.70 and porous thickness of s΄=3 cm was tested. Vertical distributions of velocity were evaluated by using a two-dimensional (2D) Particle Image Velocimetry (PIV). Velocity profiles are measured above the impermeable bed and above the sand bed for the same different total water heights (h= 6, 8, 10 and 12 cm) and for the same slope S=1.5. Measurements of mean velocity indicate the effects of the bed material used (sand bed) on the flow characteristics (Velocity distribution and Reynolds number) in comparison with those above the impermeable bed.

**Keywords:**
Particle image velocimetry,
sand bed,
velocity distribution,
Reynolds number.

##### 2697 Numerical Investigation of Hot Oil Velocity Effect on Force Heat Convection and Impact of Wind Velocity on Convection Heat Transfer in Receiver Tube of Parabolic Trough Collector System

**Authors:**
O. Afshar

**Abstract:**

A solar receiver is designed for operation under extremely uneven heat flux distribution, cyclic weather, and cloud transient cycle conditions, which can include large thermal stress and even receiver failure. In this study, the effect of different oil velocity on convection coefficient factor and impact of wind velocity on local Nusselt number by Finite Volume Method will be analyzed. This study is organized to give an overview of the numerical modeling using a MATLAB software, as an accurate, time efficient and economical way of analyzing the heat transfer trends over stationary receiver tube for different Reynolds number. The results reveal when oil velocity is below 0.33m/s, the value of convection coefficient is negligible at low temperature. The numerical graphs indicate that when oil velocity increases up to 1.2 m/s, heat convection coefficient increases significantly. In fact, a reduction in oil velocity causes a reduction in heat conduction through the glass envelope. In addition, the different local Nusselt number is reduced when the wind blows toward the concave side of the collector and it has a significant effect on heat losses reduction through the glass envelope.

**Keywords:**
Receiver tube,
heat convection,
heat conduction,
Nusselt number.

##### 2696 Critical Velocities for Particle Transport from Experiments and CFD Simulations

**Authors:**
Sajith Sajeev,
Brenton McLaury,
Siamack Shirazi

**Abstract:**

**Keywords:**
Particle transport,
critical velocity,
CFD,
DEM.

##### 2695 Cold Model Experimental Research on Particle Velocity Distribution in Gas-Solid Circulating Fluidized Bed for Methanol-to-Olefins Process

**Authors:**
Yongzheng Li,
Hongfang Ma,
Qiwen Sun,
Haitao Zhang,
Weiyong Ying

**Abstract:**

**Keywords:**
Circulating fluidized bed,
laser doppler velocimeter,
particle velocity,
radial profile.

##### 2694 Modeling the Fischer-Tropsch Reaction In a Slurry Bubble Column Reactor

**Authors:**
F. Gholami,
M. Torabi Angaji,
Z. Gholami

**Abstract:**

**Keywords:**
Modeling,
Fischer-Tropsch Synthesis,
Slurry Bubble
Column Reactor.

##### 2693 Computational Fluid Dynamics Modeling of Downward Bubbly Flows

**Authors:**
Mahmood Reza Rahimi,
Hajir Karimi

**Abstract:**

**Keywords:**
CFD,
Bubbly flow,
Vertical pipe,
Population
balance modeling,
Gas void fraction,
Liquid velocity,
Normal
turbulent stresses.

##### 2692 Low Air Velocity Measurement Characteristics- Variation Due to Flow Regime

**Authors:**
A. Pedišius,
V. Janušas,
A. Bertašienė

**Abstract:**

The paper depicts air velocity values, reproduced by laser Doppler anemometer (LDA) and ultrasonic anemometer (UA), relations with calculated ones from flow rate measurements using the gas meter which calibration uncertainty is ± (0.15 – 0.30) %. Investigation had been performed in channel installed in aerodynamical facility used as a part of national standard of air velocity. Relations defined in a research let us confirm the LDA and UA for air velocity reproduction to be the most advantageous measures. The results affirm ultrasonic anemometer to be reliable and favourable instrument for measurement of mean velocity or control of velocity stability in the velocity range of 0.05 m/s – 10 (15) m/s when the LDA used. The main aim of this research is to investigate low velocity regularities, starting from 0.05 m/s, including region of turbulent, laminar and transitional air flows. Theoretical and experimental results and brief analysis of it are given in the paper. Maximum and mean velocity relations for transitional air flow having unique distribution are represented. Transitional flow having distinctive and different from laminar and turbulent flow characteristics experimentally have not yet been analysed.

**Keywords:**
Laser Doppler anemometer,
ultrasonic anemometer,
air flow velocities,
transitional flow regime,
measurement,
uncertainty.

##### 2691 Motion Detection Techniques Using Optical Flow

**Authors:**
A. A. Shafie,
Fadhlan Hafiz,
M. H. Ali

**Abstract:**

**Keywords:**
Background modeling,
Motion detection,
Optical
flow,
Velocity smoothness constant,
motion trajectories.

##### 2690 Despiking of Turbulent Flow Data in Gravel Bed Stream

**Authors:**
Ratul Das

**Abstract:**

The present experimental study insights the decontamination of instantaneous velocity fluctuations captured by Acoustic Doppler Velocimeter (ADV) in gravel-bed streams to ascertain near-bed turbulence for low Reynolds number. The interference between incidental and reflected pulses produce spikes in the ADV data especially in the near-bed flow zone and therefore filtering the data are very essential. Nortek’s Vectrino four-receiver ADV probe was used to capture the instantaneous three-dimensional velocity fluctuations over a non-cohesive bed. A spike removal algorithm based on the acceleration threshold method was applied to note the bed roughness and its influence on velocity fluctuations and velocity power spectra in the carrier fluid. The velocity power spectra of despiked signals with a best combination of velocity threshold (VT) and acceleration threshold (AT) are proposed which ascertained velocity power spectra a satisfactory fit with the Kolmogorov “–5/3 scaling-law” in the inertial sub-range. Also, velocity distributions below the roughness crest level fairly follows a third-degree polynomial series.

**Keywords:**
Acoustic Doppler Velocimeter,
gravel-bed,
spike removal,
Reynolds shear stress,
near-bed turbulence,
velocity power spectra.

##### 2689 Characteristics of Turbulent Round Jets in its Potential-Core Region

**Authors:**
S. Sivakumar,
Ravikiran Sangras,
Vasudevan Raghavan

**Abstract:**

**Keywords:**
Contoured nozzle,
hot-wire anemometer,
Reynolds
number,
velocity fluctuations,
velocity spectra.

##### 2688 Terminal Velocity of a Bubble Rise in a Liquid Column

**Authors:**
Mário A. R. Talaia

**Abstract:**

**Keywords:**
Bubbles,
terminal velocity,
two phase-flow,
vertical
column.

##### 2687 Evaluation of Carbon Dioxide Pressure through Radial Velocity Difference in Arterial Blood Modeled by Drift Flux Model

**Authors:**
Aicha Rima Cheniti,
Hatem Besbes,
Joseph Haggege,
Christophe Sintes

**Abstract:**

**Keywords:**
Mean carbon dioxide pressure,
mean mixture pressure,
mixture velocity,
radial velocity difference.

##### 2686 Measurement of Steady Streaming from an Oscillating Bubble Using Particle Image Velocimetry

**Authors:**
Yongseok Kwon,
Woowon Jeong,
Eunjin Cho,
Sangkug Chung,
Kyehan Rhee

**Abstract:**

Steady streaming flow fields induced by a 500 mm bubble oscillating at 12 kHz were measured using microscopic particle image velocimetry (PIV). The accuracy of velocity measurement using a micro PIV system was checked by comparing the measured velocity fields with the theoretical velocity profiles in fully developed laminar flow. The steady streaming flow velocities were measured in the sagittal plane of the bubble attached on the wall. Measured velocity fields showed upward jet flow with two symmetric counter-rotating vortices, and the maximum streaming velocity was about 12 mm/s, which was within the velocity ranges measured by other researchers. The measured streamlines were compared with the analytical solution, and they also showed a reasonable agreement.

**Keywords:**
Oscillating bubble,
Particle-Image-Velocimetry microstreaming.

##### 2685 Modeling of Blood Flow Velocity into the Main Artery via Left Ventricle of Heart during Steady Condition

**Authors:**
Mohd Azrul Hisham Mohd Adib,
Nur Hazreen Mohd Hasni

**Abstract:**

A three-dimensional and pulsatile blood flow in the left ventricle of heart model has been studied numerically. The geometry was derived from a simple approximation of the left ventricle model and the numerical simulations were obtained using a formulation of the Navier-Stokes equations. In this study, simulation was used to investigate the pattern of flow velocity in 3D model of heart with consider the left ventricle based on critical parameter of blood under steady condition. Our results demonstrate that flow velocity focused from mitral valve channel and continuous linearly to left ventricle wall but this skewness progresses into outside wall in atrium through aortic valve with random distribution that is irregular due to force subtract from ventricle wall during cardiac cycle. The findings are the prediction of the behavior of the blood flow velocity pattern in steady flow condition which can assist the medical practitioners in their decision on the patients- treatments.

**Keywords:**
Mitral Valve,
Aortic Valve,
Cardiac Cycle,
Leaflet,
Biomechanics,
Left Ventricle

##### 2684 Investigation of Self-Similarity Solution for Wake Flow of a Cylinder

**Authors:**
A. B. Khoshnevis,
F. Zeydabadi,
F. Sokhanvar

**Abstract:**

**Keywords:**
Self-similarity,
wake of single circular cylinder

##### 2683 Mean Velocity Modeling of Open-Channel Flow with Submerged Rigid Vegetation

**Authors:**
M. Morri,
A. Soualmia,
P. Belleudy

**Abstract:**

Vegetation affects the mean and turbulent flow structure. It may increase flood risks and sediment transport. Therefore, it is important to develop analytical approaches for the bed shear stress on vegetated bed, to predict resistance caused by vegetation. In the recent years, experimental and numerical models have both been developed to model the effects of submerged vegetation on open-channel flow. In this paper, different analytic models are compared and tested using the criteria of deviation, to explore their capacity for predicting the mean velocity and select the suitable one that will be applied in real case of rivers. The comparison between the measured data in vegetated flume and simulated mean velocities indicated, a good performance, in the case of rigid vegetation, whereas, Huthoff model shows the best agreement with a high coefficient of determination (R2=80%) and the smallest error in the prediction of the average velocities.

**Keywords:**
Analytic Models,
Comparison,
Mean Velocity,
Vegetation.

##### 2682 An Investigation on the Effects of Injection Spray Cone on Propulsive Droplets in a Duct

**Authors:**
M. Mojtahedpoor

**Abstract:**

**Keywords:**
Ramjet,
droplet sizing,
injection velocity,
air flowvelocity,
efficient mass fraction..

##### 2681 Gas Pressure Evaluation through Radial Velocity Measurement of Fluid Flow Modeled by Drift Flux Model

**Authors:**
Aicha Rima Cheniti,
Hatem Besbes,
Joseph Haggege,
Christophe Sintes

**Abstract:**

In this paper, we consider a drift flux mixture model of the blood flow. The mixture consists of gas phase which is carbon dioxide and liquid phase which is an aqueous carbon dioxide solution. This model was used to determine the distributions of the mixture velocity, the mixture pressure, and the carbon dioxide pressure. These theoretical data are used to determine a measurement method of mean gas pressure through the determination of radial velocity distribution. This method can be applicable in experimental domain.

**Keywords:**
Mean carbon dioxide pressure,
mean mixture pressure,
mixture velocity,
radial velocity.

##### 2680 Flow of a Second Order Fluid through Constricted Tube with Slip Velocity at Wall Using Integral Method

**Authors:**
Nosheen Zareen Khan,
Abdul Majeed Siddiqui,
Muhammad Afzal Rana

**Abstract:**

**Keywords:**
Approximate solution,
constricted tube,
non-Newtonian fluids,
Reynolds number.

##### 2679 Non-Linear Vibration and Stability Analysis of an Axially Moving Beam with Rotating-Prismatic Joint

**Authors:**
M. Najafi,
F. Rahimi Dehgolan

**Abstract:**

In this paper, the dynamic modeling of a single-link flexible beam with a tip mass is given by using Hamilton's principle. The link has been rotational and translational motion and it was assumed that the beam is moving with a harmonic velocity about a constant mean velocity. Non-linearity has been introduced by including the non-linear strain to the analysis. Dynamic model is obtained by Euler-Bernoulli beam assumption and modal expansion method. Also, the effects of rotary inertia, axial force, and associated boundary conditions of the dynamic model were analyzed. Since the complex boundary value problem cannot be solved analytically, the multiple scale method is utilized to obtain an approximate solution. Finally, the effects of several conditions on the differences among the behavior of the non-linear term, mean velocity on natural frequencies and the system stability are discussed.

**Keywords:**
Non-linear vibration,
stability,
axially moving beam,
bifurcation,
multiple scales method.