**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**825

# Search results for: velocity.

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

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

**Abstract:**

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

##### 824 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.

##### 823 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.

##### 822 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.

##### 821 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.

##### 820 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.

##### 819 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.

##### 818 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.

##### 817 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.

##### 816 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.

##### 815 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

##### 814 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.

##### 813 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.

##### 812 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.

##### 811 Homotopy Analysis Method for Hydromagnetic Plane and Axisymmetric Stagnation-point Flow with Velocity Slip

**Authors:**
Jing Zhu,
Liancun Zheng,
Xinxin Zhang

**Abstract:**

**Keywords:**
slip flow,
axisymmetric flow,
homotopy analysismethod,
stagnation-point.

##### 810 Hydraulic Analysis on Microhabitat of Benthic Macroinvertebrates at Riparian Riffles

**Authors:**
Jin-Hong Kim

**Abstract:**

Hydraulic analysis on microhabitat of Benthic Macro- invertebrates was performed at riparian riffles of Hongcheon River and Gapyeong Stream. As for the representative species, *Ecdyonurus kibunensis*, *Paraleptophlebia cocorata*, *Chironomidae *sp. and *Psilotreta kisoensis iwata* were chosen. They showed hydraulically different habitat types by flow velocity and particle diameters of streambed materials. Habitat conditions of the swimmers were determined mainly by the flow velocity rather than by flow depth or by riverbed materials. Burrowers prefer sand and silt, and inhabited at the riverbed. Sprawlers prefer cobble or boulder and inhabited for velocity of 0.05-0.15 m/s. Clingers prefer pebble or cobble and inhabited for velocity of 0.06-0.15 m/s. They were found to be determined mainly by the flow velocity.

**Keywords:**
Benthic macroinvertebrates,
riffles,
clinger,
swimmer,
burrower,
sprawler.

##### 809 Effect of Adverse Pressure Gradient on a Fluctuating Velocity over the Co-Flow Jet Airfoil

**Authors:**
Morteza Mirhosseini,
Amir B. Khoshnevis

**Abstract:**

^{o}and this has due to the jet energized, while the angle of attack 20

^{o}has different. The airfoil cord based Reynolds number has 10

^{5}.

**Keywords:**
Adverse pressure gradient,
fluctuating velocity,
wall jet,
co-flow jet airfoil.

##### 808 One Some Effective Solutions of Stokes Axisymmetric Equation for a Viscous Fluid

**Authors:**
N. Khatiashvili,
K. Pirumova,
D. Janjgava

**Abstract:**

The Stokes equation connected with the fluid flow over the axisymmetric bodies in a cylindrical area is considered. The equation is studied in a moving coordinate system with the appropriate boundary conditions. Effective formulas for the velocity components are obtained. The graphs of the velocity components and velocity profile are plotted.

**Keywords:**
Stokes system,
viscous fluid.

##### 807 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.

##### 806 Distortion of Flow Measurement and Cavitation Occurs Due to Orifice Inlet Velocity Profiles

**Authors:**
Byung-Soo Shin,
Nam-Seok Kim,
Sang-Kyu Lee,
O-Hyun Keum

**Abstract:**

**Keywords:**
Orifice,
k-e model,
CFD

##### 805 Stress Analysis for Two Fitted Thin Walled Cylinder with High Angular Velocity

**Authors:**
A.V. Hoseini,
A. Bidi,
M. H. Pol,
M.Jalali azizpour

**Abstract:**

**Keywords:**
Thin walled cylinder,
high angular velocity,
twofitted thin walled

##### 804 Velocity Distribution in Open Channels: Combination of Log-law and Parabolic-law

**Authors:**
Snehasis Kundu,
Koeli Ghoshal

**Abstract:**

In this paper, based on flume experimental data, the velocity distribution in open channel flows is re-investigated. From the analysis, it is proposed that the wake layer in outer region may be divided into two regions, the relatively weak outer region and the relatively strong outer region. Combining the log law for inner region and the parabolic law for relatively strong outer region, an explicit equation for mean velocity distribution of steady and uniform turbulent flow through straight open channels is proposed and verified with the experimental data. It is found that the sediment concentration has significant effect on velocity distribution in the relatively weak outer region.

**Keywords:**
Inner and outer region,
Log law,
Parabolic law,
Richardson number.

##### 803 Linear Stability Characteristics of Wake-Shear Layers in Two-Phase Shallow Flows

**Authors:**
Inta Volodko,
Valentina Koliskina

**Abstract:**

**Keywords:**
Linear stability,
Shallow flows,
Wake-shear flows.

##### 802 Effect of Baffles on the Cooling of Electronic Components

**Authors:**
O. Bendermel,
C. Seladji,
M. Khaouani

**Abstract:**

In this work, we made anumerical study of the thermal and dynamic behavior of air in a horizontal channel with electronic components.The influenceto use baffles on the profiles of velocity and temperature is discussed.The finite volume method and the algorithm Simple are used for solving the equations of conservation of mass, momentum and energy.The results found show that baffles improve heat transfer between the cooling air and electronic components. The velocity will increase from 3 times per rapport of the initial velocity.

**Keywords:**
Electronic components,
baffles,
cooling.

##### 801 Generalized Stokes’ Problems for an Incompressible Couple Stress Fluid

**Authors:**
M.Devakar,
T.K.V.Iyengar

**Abstract:**

In this paper, we investigate the generalized Stokes’ problems for an incompressible couple stress fluid. Analytical solution of the governing equations is obtained in Laplace transform domain for each problem. A standard numerical inversion technique is used to invert the Laplace transform of the velocity in each case. The effect of various material parameters on velocity is discussed and the results are presented through graphs. It is observed that, the results are in tune with the observation of V.K.Stokes in connection with the variation of velocity in the flow between two parallel plates when the top one is moving with constant velocity and the bottom one is at rest.

**Keywords:**
Couple stress fluid,
Generalized Stokes’ problems,
Laplace transform,
Numerical inversion

##### 800 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.

##### 799 Soil Moisture Regulation in Irrigated Agriculture

**Authors:**
I. Kruashvili,
I. Inashvili,
K. Bziava,
M. Lomishvili

**Abstract:**

Seepage capillary anomalies in the active layer of soil, related to the soil water movement, often cause variation of soil hydrophysical properties and become one of the main objectives of the hydroecology. It is necessary to mention that all existing equations for computing the seepage flow particularly from soil channels, through dams, bulkheads, and foundations of hydraulic engineering structures are preferable based on the linear seepage law. Regarding the existing beliefs, anomalous seepage is based on postulates according to which the fluid in free volume is characterized by resistance against shear deformation and is presented in the form of initial gradient. According to the above-mentioned information, we have determined: Equation to calculate seepage coefficient when the velocity of transition flow is equal to seepage flow velocity; by means of power function, equations for the calculation of average and maximum velocities of seepage flow have been derived; taking into consideration the fluid continuity condition, average velocity for calculation of average velocity in capillary tube has been received.

**Keywords:**
Seepage,
soil,
velocity,
water.

##### 798 Vehicle Velocity Estimation for Traffic Surveillance System

**Authors:**
H. A. Rahim,
U. U. Sheikh,
R. B. Ahmad,
A. S. M. Zain

**Abstract:**

This paper describes an algorithm to estimate realtime vehicle velocity using image processing technique from the known camera calibration parameters. The presented algorithm involves several main steps. First, the moving object is extracted by utilizing frame differencing technique. Second, the object tracking method is applied and the speed is estimated based on the displacement of the object-s centroid. Several assumptions are listed to simplify the transformation of 2D images from 3D real-world images. The results obtained from the experiment have been compared to the estimated ground truth. From this experiment, it exhibits that the proposed algorithm has achieved the velocity accuracy estimation of about ± 1.7 km/h.

**Keywords:**
camera calibration,
object tracking,
velocity estimation,
video image processing

##### 797 On the Flow of a Third Grade Viscoelastic Fluid in an Orthogonal Rheometer

**Authors:**
Carmen D. Pricinâ,
E. Corina Cipu,
Victor Ţigoiu

**Abstract:**

The flow of a third grade fluid in an orthogonal rheometer is studied. We employ the admissible velocity field proposed in [5]. We solve the problem and obtain the velocity field as well as the components for the Cauchy tensor. We compare the results with those from [9]. Some diagrams concerning the velocity and Cauchy stress components profiles are presented for different values of material constants and compared with the corresponding values for a linear viscous fluid.

**Keywords:**
Non newtonian fluid flow,
orthogonal rheometer,
third grade fluid.

##### 796 Investigation on Nanoparticle Velocity in Two Phase Approach

**Authors:**
E. Mat Tokit,
Yusoff M. Z,
Mohammed H.

**Abstract:**

Numerical investigation on the generality of nanoparticle velocity equation had been done on the previous published work. The three dimensional governing equations (continuity, momentum and energy) were solved using finite volume method (FVM). Parametric study of thermal performance between pure water-cooled and nanofluid-cooled are evaluated for volume fraction in the range of 1% to 4%, and nanofluid type of gamma-Al_{2}O_{3 }at Reynolds number range of 67.41 to 286.77. The nanofluid is modeled using single and two phase approach. Three different existing Brownian motion velocities are applied in comparing the generality of the equation for a wide parametric condition. Deviation in between the Brownian motion velocity is identified to be due to the different means of mean free path and constant value used in diffusion equation.

**Keywords:**
Brownian nanoparticle velocity,
heat transfer enhancement,
nanofluid,
two phase model.