**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**2996

# Search results for: Velocity field

##### 2996 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.

##### 2995 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.

##### 2994 Numerical Simulation of Flow Field in a Elliptic Bottom Stirred Tank with Bottom Baffles

**Authors:**
Liu Xuedong ,
Liu Zhiyan

**Abstract:**

**Keywords:**
Bottom baffle,
Flow field,
Numerical simulation,
Stirred tank.

##### 2993 Velocity Filter Banks using 3-D FFT

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

**Abstract:**

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

##### 2992 Flow Field Analysis of Submerged Horizontal Plate Type Breakwater

**Authors:**
Ke Wang,
Zhi-Qiang Zhang,
Z. Chen

**Abstract:**

**Keywords:**
boundary element method,
plate type breakwater,
flow field analysis

##### 2991 Exact Solution of Some Helical Flows of Newtonian Fluids

**Authors:**
Imran Siddique

**Abstract:**

**Keywords:**
Newtonian fluids,
Velocity field,
Exact solutions,
Shear stress,
Cylindrical domains.

##### 2990 Investigation of Corona wind Effect on Heat and Mass Transfer Enhancement

**Authors:**
R.Karami,
B.Kamkari,
K.Kashefi

**Abstract:**

**Keywords:**
Electrohydodynamics (EHD),
corona wind,
high
electric field,
Evaporation enhancement

##### 2989 Stochastic Estimation of Cavity Flowfield

**Authors:**
Yin Yin Pey,
Leok Poh Chua,
Wei Long Siauw

**Abstract:**

**Keywords:**
Open cavity,
Particle Image Velocimetry,
Stochastic
estimation,
Turbulent kinetic energy.

##### 2988 The Role of Velocity Map Quality in Estimation of Intravascular Pressure Distribution

**Authors:**
Ali Pashaee,
Parisa Shooshtari,
Gholamreza Atae,
Nasser Fatouraee

**Abstract:**

**Keywords:**
Flow imaging,
pressure distribution estimation,
phantom,
resolution.

##### 2987 Thermosolutal MHD Mixed Marangoni Convective Boundary Layers in the Presence of Suction or Injection

**Authors:**
Noraini Ahmad,
Seripah Awang Kechil,
Norma Mohd Basir

**Abstract:**

**Keywords:**
Magnetic field,
mixed Marangoni convection,
similarity boundary layers,
solute concentration.

##### 2986 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.

##### 2985 Hydrothermal Behavior of G-S Magnetically Stabilized Beds Consisting of Magnetic and Non-Magnetic Admixtures

**Authors:**
Z. Al-Qodah,
M. Al-Busoul,
A. Khraewish

**Abstract:**

**Keywords:**
Magnetic stabilization; Magnetic stabilized fluidizedbeds; Gas-fluidized beds.

##### 2984 Experimental Study of Unconfined and Confined Isothermal Swirling Jets

**Authors:**
Rohit Sharma,
Fabio Cozzi

**Abstract:**

A 3C-2D PIV technique was applied to investigate the swirling flow generated by an axial plus tangential type swirl generator. This work is focused on the near-exit region of an isothermal swirling jet to characterize the effect of swirl on the flow field and to identify the large coherent structures both in unconfined and confined conditions for geometrical swirl number, S_{g }= 4.6. Effects of the Reynolds number on the flow structure were also studied. The experimental results show significant effects of the confinement on the mean velocity fields and its fluctuations. The size of the recirculation zone was significantly enlarged upon confinement compared to the free swirling jet. Increasing in the Reynolds number further enhanced the recirculation zone. The frequency characteristics have been measured with a capacitive microphone which indicates the presence of periodic oscillation related to the existence of precessing vortex core, PVC. Proper orthogonal decomposition of the jet velocity field was carried out, enabling the identification of coherent structures. The time coefficients of the first two most energetic POD modes were used to reconstruct the phase-averaged velocity field of the oscillatory motion in the swirling flow. The instantaneous minima of negative swirl strength values calculated from the instantaneous velocity field revealed the presence of two helical structures located in the inner and outer shear layers and this structure fade out at an axial location of approximately z/D = 1.5 for unconfined case and z/D = 1.2 for confined case. By phase averaging the instantaneous swirling strength maps, the 3D helical vortex structure was reconstructed.

**Keywords:**
Acoustic probes,
3C-2D particle image velocimetry,
PIV,
precessing vortex core,
PVC,
recirculation zone.

##### 2983 A Comparison Study of a Symmetry Solution of Magneto-Elastico-Viscous Fluid along a Semi- Infinite Plate with Homotopy Perturbation Method and4th Order Runge–Kutta Method

**Authors:**
Mohamed M. Mousa,
Aidarkhan Kaltayev

**Abstract:**

The equations governing the flow of an electrically conducting, incompressible viscous fluid over an infinite flat plate in the presence of a magnetic field are investigated using the homotopy perturbation method (HPM) with Padé approximants (PA) and 4th order Runge–Kutta method (4RKM). Approximate analytical and numerical solutions for the velocity field and heat transfer are obtained and compared with each other, showing excellent agreement. The effects of the magnetic parameter and Prandtl number on velocity field, shear stress, temperature and heat transfer are discussed as well.

**Keywords:**
Electrically conducting elastico-viscous fluid,
symmetry solution,
Homotopy perturbation method,
Padé
approximation,
4th order Runge–Kutta,
Maple

##### 2982 A Refined Nonlocal Strain Gradient Theory for Assessing Scaling-Dependent Vibration Behavior of Microbeams

**Authors:**
Xiaobai Li,
Li Li,
Yujin Hu,
Weiming Deng,
Zhe Ding

**Abstract:**

**Keywords:**
Euler-Bernoulli Beams,
free vibration,
higher order
inertia,
nonlocal strain gradient theory,
velocity gradient.

##### 2981 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.

##### 2980 Reconstruction of the Most Energetic Modes in a Fully Developed Turbulent Channel Flow with Density Variation

**Authors:**
Elteyeb Eljack,
Takashi Ohta

**Abstract:**

Proper orthogonal decomposition (POD) is used to reconstruct spatio-temporal data of a fully developed turbulent channel flow with density variation at Reynolds number of 150, based on the friction velocity and the channel half-width, and Prandtl number of 0.71. To apply POD to the fully developed turbulent channel flow with density variation, the flow field (velocities, density, and temperature) is scaled by the corresponding root mean square values (rms) so that the flow field becomes dimensionless. A five-vector POD problem is solved numerically. The reconstructed second-order moments of velocity, temperature, and density from POD eigenfunctions compare favorably to the original Direct Numerical Simulation (DNS) data.

**Keywords:**
Pattern Recognition,
POD,
Coherent Structures,
Low dimensional modelling.

##### 2979 Plastic Flow through Taper Dies: A Threedimensional Analysis

**Authors:**
Laxmi Narayan Patra,
Susanta Kumar Sahoo,
Mithun KumarMurmu

**Abstract:**

**Keywords:**
Extrusion,
Kinematically admissibly velocity fieldSpatial Elementary Rigid Region (SERR),
Upper Bound Analysis

##### 2978 Steering Velocity Bounded Mobile Robots in Environments with Partially Known Obstacles

**Authors:**
Reza Hossseynie,
Amir Jafari

**Abstract:**

**Keywords:**
Steering,
obstacle avoidance,
mobile robots,
constrained directions control,
artificial potential field.

##### 2977 Evaluation of Aerodynamic Noise Generation by a Generic Side Mirror

**Authors:**
Yiping Wang,
Zhengqi Gu,
Weiping Li,
Xiaohui Lin

**Abstract:**

The aerodynamic noise radiation from a side view mirror (SVM) in the high-speed airflow is calculated by the combination of unsteady incompressible fluid flow analysis and acoustic analysis. The transient flow past the generic SVM is simulated with variable turbulence model, namely DES Detached Eddy Simulation and LES (Large Eddy Simulation). Detailed velocity vectors and contour plots of the time-varying velocity and pressure fields are presented along cut planes in the flow-field. Mean and transient pressure are also monitored at several points in the flow field and compared to corresponding experimentally data published in literature. The acoustic predictions made using the Ffowcs-Williams-Hawkins acoustic analogy (FW-H) and the boundary element (BEM).

**Keywords:**
Aerodynamic noise,
BEM,
DES,
FW-H acousticanalogy,
LES

##### 2976 Experimental Measurements of the Mean Flow Field in Wide-Angled Diffusers: A Data Bank Contribution

**Authors:**
Karanja Kibicho,
Anthony Sayers

**Abstract:**

**Keywords:**
Two-dimensional,
wide-angled,
diffuser,
stall,
separated
flows,
subsonic flows,
diffuser flow regimes

##### 2975 Unsteady Transient Free Convective Flow of an Incompressible Viscous Fluid under Influence of Uniform Transverse Magnetic Field

**Authors:**
Praveen Saraswat,
Vipin Kumar Verma,
Rudraman Singh

**Abstract:**

The unsteady transient free convection flow of an incompressible dissipative viscous fluid between parallel plates at different distances have been investigated under porous medium. Due to presence of heat flux under the influence of uniform transverse magnetic field the velocity distribution and the temperature distribution, is shown graphically. Since exact solution is not possible so we find parametrical solution by perturbation technique. The result is shown in graph for different parameters. We notice that heat generation effects fluid velocity keeping in which of free convection which cools.

**Keywords:**
Transient,
Convection,
MHD,
Viscous,
Porous.

##### 2974 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.

##### 2973 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.

##### 2972 Magnetohydrodynamic Free Convection in a Square Cavity Heated from Below and Cooled from Other Walls

**Authors:**
S. Jani,
M. Mahmoodi,
M. Amini

**Abstract:**

Magnetohydrodynamic free convection fluid flow and heat transfer in a square cavity filled with an electric conductive fluid with Prandtl number of 0.7 has been investigated numerically. The horizontal bottom wall of the cavity was kept at Th while the side and the top walls of the cavity were maintained at a constant temperature Tc with Th>Tc. The governing equations written in terms of the primitive variables were solved numerically using the finite volume method while the SIMPLER algorithm was used to couple the velocity and pressure fields. Using the developed code, a parametric study was performed, and the effects of the Rayleigh number and the Hartman number on the fluid flow and heat transfer inside the cavity were investigated. The obtained results showed that temperature distribution and flow pattern inside the cavity depended on both strength of the magnetic field and Rayleigh number. For all cases two counter rotating eddies were formed inside the cavity. The magnetic field decreased the intensity of free convection and flow velocity. Also it was found that for higher Rayleigh numbers a relatively stronger magnetic field was needed to decrease the heat transfer through free convection.

**Keywords:**
Free Convection,
Magnetic Field,
Square Cavity,
Numerical Simulation.

##### 2971 Spectral Investigation for Boundary Layer Flow over a Permeable Wall in the Presence of Transverse Magnetic Field

**Authors:**
Saeed Sarabadan,
Mehran Nikarya,
Kouroah Parand

**Abstract:**

**Keywords:**
MHD Falkner-Skan,
nonlinear ODE,
spectral
collocation method,
Bessel functions,
skin friction,
velocity.

##### 2970 Orbit Propagator and Geomagnetic Field Estimator for NanoSatellite: The ICUBE Mission

**Authors:**
Lv Meibo,
Naqvi Najam Abbas,
Hina Arshad,
Li YanJun

**Abstract:**

This research contribution is drafted to present the orbit design, orbit propagator and geomagnetic field estimator for the nanosatellites specifically for the upcoming CUBESAT, ICUBE-1 of the Institute of Space Technology (IST), Islamabad, Pakistan. The ICUBE mission is designed for the low earth orbit at the approximate height of 700KM. The presented research endeavor designs the Keplarian elements for ICUBE-1 orbit while incorporating the mission requirements and propagates the orbit using J2 perturbations, The attitude determination system of the ICUBE-1 consists of attitude determination sensors like magnetometer and sun sensor. The Geomagnetic field estimator is developed according to the model of International Geomagnetic Reference Field (IGRF) for comparing the magnetic field measurements by the magnetometer for attitude determination. The output of the propagator namely the Keplarians position and velocity vectors and the magnetic field vectors are compared and verified with the same scenario generated in the Satellite Tool Kit (STK).

**Keywords:**
CUBESAT,
Geomagnetic Field,
ICUBE-1,
Orbit
Propagator,
Satellite.

##### 2969 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.

##### 2968 A Parametric Study on Deoiling Hydrocyclones Flow Field

**Authors:**
Maysam Saidi,
Reza Maddahian,
Bijan Farhanieh

**Abstract:**

Hydrocyclones flow field study is conducted by performing a parametric study. Effect of cone angle on deoiling hydrocyclones flow behaviour is studied in this research. Flow field of hydrocyclone is obtained by three-dimensional simulations with OpenFOAM code. Because of anisotropic behaviour of flow inside hydrocyclones LES is a suitable method to predict the flow field since it resolves large scales and model isotropic small scales. Large eddy simulation is used to predict the flow behavior of three different cone angles. Differences in tangential velocity and pressure distribution are reported in some figures.

**Keywords:**
Deoiling hydrocyclones,
Flow field,
Hydrocyclone
cone angle,
Large Eddy Simulation,
Pressure distribution

##### 2967 DQ Analysis of 3D Natural Convection in an Inclined Cavity Using an Velocity-Vorticity Formulation

**Abstract:**

In this paper, the differential quadrature method is applied to simulate natural convection in an inclined cubic cavity using velocity-vorticity formulation. The numerical capability of the present algorithm is demonstrated by application to natural convection in an inclined cubic cavity. The velocity Poisson equations, the vorticity transport equations and the energy equation are all solved as a coupled system of equations for the seven field variables consisting of three velocities, three vorticities and temperature. The coupled equations are simultaneously solved by imposing the vorticity definition at boundary without requiring the explicit specification of the vorticity boundary conditions. Test results obtained for an inclined cubic cavity with different angle of inclinations for Rayleigh number equal to 103, 104, 105 and 106 indicate that the present coupled solution algorithm could predict the benchmark results for temperature and flow fields. Thus, it is convinced that the present formulation is capable of solving coupled Navier-Stokes equations effectively and accurately.

**Keywords:**
Natural convection,
velocity-vorticity formulation,
differential quadrature (DQ).