**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**947

# Search results for: raindrop fall velocity.

##### 947 The Effect of Raindrop Kinetic Energy on Soil Erodibility

**Authors:**
A. Moussouni,
L. Mouzai,
M. Bouhadef

**Abstract:**

Soil erosion is a very complex phenomenon, resulting from detachment and transport of soil particles by erosion agents. The kinetic energy of raindrop is the energy available for detachment and transport by splashing rain. The soil erodibility is defined as the ability of soil to resist to erosion. For this purpose, an experimental study was conducted in the laboratory using rainfall simulator to study the effect of the kinetic energy of rain (Ec) on the soil erodibility (K). The soil used was a sandy agricultural soil of 62.08% coarse sand, 19.14% fine sand, 6.39% fine silt, 5.18% coarse silt and 7.21% clay. The obtained results show that the kinetic energy of raindrops evolves as a power law with soil erodibility.

**Keywords:**
Erosion,
runoff,
raindrop kinetic energy,
soil
erodibility,
rainfall intensity,
raindrop fall velocity.

##### 946 Harvesting of Kinetic Energy of the Raindrops

**Authors:**
K. C. R. Perera,
B. G. Sampath,
V. P. C. Dassanayake,
B. M. Hapuwatte.

**Abstract:**

This paper presents a methodology to harvest the kinetic energy of the raindrops using piezoelectric devices. In the study 1m×1m PVDF (Polyvinylidene fluoride) piezoelectric membrane, which is fixed by the four edges, is considered for the numerical simulation on deformation of the membrane due to the impact of the raindrops. Then according to the drop size of the rain, the simulation is performed classifying the rainfall types into three categories as light stratiform rain, moderate stratiform rain and heavy thundershower. The impact force of the raindrop is dependent on the terminal velocity of the raindrop, which is a function of raindrop diameter. The results were then analyzed to calculate the harvestable energy from the deformation of the piezoelectric membrane.

**Keywords:**
Raindrop,
piezoelectricity,
deformation,
terminal velocity.

##### 945 Determination of the Gain in Learning the Free-Fall Motion of Bodies by Applying the Resource of Previous Concepts

**Authors:**
Ricardo Merlo

**Abstract:**

In this paper, we analyzed the different didactic proposals for teaching about the free fall motion of bodies available online. An important aspect was the interpretation of the direction and sense of the acceleration of gravity and of the falling velocity of a body, which is why we found different applications of the Cartesian reference system used and also different graphical presentations of the velocity as a function of time and of the distance traveled vertically by the body in the period of time that it was dropped from a height h0. In this framework, a survey of previous concepts was applied to a voluntary group of first-year university students of an Engineering degree before and after the development of the class of the subject in question. Then, Hake's index (0.52) was determined, which resulted in an average learning gain from the meaningful use of the reference system and the respective graphs of velocity versus time and height versus time.

**Keywords:**
Didactic gain,
free–fall,
physics teaching,
previous knowledge.

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

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

**Abstract:**

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

##### 943 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.

##### 942 State of the Art: A Study on Fall Detection

**Authors:**
Goh Yongli,
Ooi Shih Yin,
Pang Ying Han

**Abstract:**

**Keywords:**
State of the art,
fall detection,
wearable devices,
ambient analyser,
motion detection.

##### 941 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.

##### 940 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.

##### 939 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.

##### 938 An Efficient Fall Detection Method for Elderly Care System

**Authors:**
S. Sowmyayani,
P. Arockia Jansi Rani

**Abstract:**

**Keywords:**
Pearson correlation coefficient,
motion history image,
human shape identification.

##### 937 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.

##### 936 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.

##### 935 An FPGA Implementation of Intelligent Visual Based Fall Detection

**Authors:**
Peng Shen Ong,
Yoong Choon Chang,
Chee Pun Ooi,
Ettikan K. Karuppiah,
Shahirina Mohd Tahir

**Abstract:**

**Keywords:**
Fall detection,
FPGA,
hardware implementation.

##### 934 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.

##### 933 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.

##### 932 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.

##### 931 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

##### 930 Finite Element Prediction of Hip Fracture during a Sideways Fall

**Authors:**
M. Ikhwan Z. Ridzwan,
Bidyut Pal,
Ulrich N. Hansen

**Abstract:**

**Keywords:**
Femoral Strength,
Finite Element Models,
Hip
Fracture,
Progressive Failure,
Sideways Fall.

##### 929 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.

##### 928 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.

##### 927 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.

##### 926 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.

##### 925 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.

##### 924 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.

##### 923 Yield Performance of Two Locally Adapted and Two Introductions of Common Cowpea in Response to Amended In-Row-Spaces and Planting Dates

**Authors:**
Mohamed M. A. Abdalla,
M. F Mohamed,
A. M. A. Rashwan

**Abstract:**

A field experiment was conducted in the Agricultural Research Station, at El-Ghoraieb, Assiut to study dry seed yield performance of two locally adapted cultivars (‘Azmerly’ and ‘Cream 7’) and two line introductions (IT81D-1032 and IT82D-812) of common cowpea (Vigna unguiculata (L.) Walp) grown at three different within-row spaces (20, 30 and 40 cm) and two planting dates in the summer (April 15th and 30th) and in the fall season (Aug. 12th and 27th) of two successive seasons. The data showed that total dry-seed yield produced by plants grown at 20 cm was greater than at 30 cm in all cvs/lines in both years. Increases in 1000-seed weight were detected in cv ‘Azmerly’ and line IT82D-812 when they were grown at 30 cm as compared with 20 cm in the summer season. However, in the fall season such increases were found in all cvs/lines. Planting at 40 cm produced seeds of greater weight than planting at 30 cm for all cvs/lines in the fall season and also in cv. Cream 7 and line IT82D-812 in the summer season, while all cvs/lines in the fall Planting on April 15th in the summer and also planting on Aug. 12th in the fall had plants which showed increases in 1000-seed weight and total dry-seed yield. The greatest 1000-seed weight was found in the line IT81D-1032 in the summer season and in the line IT82D-812 in the fall season. The sum up results revealed that ‘Azmerly’ produced greater dry-seed yield than ‘Cream 7’ and both of them were superior to the line IT82D-812 and IT81D-1032 in the summer season. In the fall, however, the line IT82D-812 produced greater dry-seed yield than the other cultivars/lines.

**Keywords:**
Cowpea,
Assiut,
fall,
planting dates,
El-Ghoraieb.

##### 922 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.

##### 921 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.

##### 920 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

##### 919 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

##### 918 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.