scholarly journals Experimental Investigation of the Effect of Ice Blockage on Propeller Hydrodynamic Performance

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Chun-Yu Guo ◽  
Pei Xu ◽  
Chao Wang ◽  
Wei-Peng Xiong
Keyword(s):  
Transverse Direction ◽  
Particle Image ◽  
Fluid Velocity ◽  
Vertical Direction ◽  
Wake Flow ◽  
Hydrodynamic Performance ◽  
Propeller Wake ◽  
Image Velocimetry ◽  
Measurement Results ◽  
Thrust And Torque

This experimental study investigates the influence of different sizes, quantities, and axial positions of model ice on propeller hydrodynamic performance. We used particle image velocimetry measurements to analyze the characteristics of the propeller wake flow field. The measurement results show that ice blockage leads to an increase in propeller thrust, torque, and efficiency. The smaller the advance coefficient of the propeller is, the smaller the influence of model ice on propeller blockage is. As the model ice becomes thicker and the thrust and efficiency of the propeller increase, the propeller torque is smaller for low advance coefficient and higher for high advance coefficient. The wider the model ice is, the larger the thrust and torque of the propeller are. Once the model ice width exceeds the propeller diameter, the change in its width has no effect on propeller efficiency. When the propeller is blocked with model ice, the fluid velocity in the wake flow reduces in the inflow direction, and the increase in fluid velocity in the horizontal transverse direction and variation of fluid velocity in the vertical direction are related to the model ice width.

Numerical investigation of the rake angle effect on the hydrodynamic performance of propeller in a uniform and nonuniform flow

2019 ◽  
Vol 233 (18) ◽  
pp. 6326-6338
Author(s):  
Hasan Sajedi ◽  
Miralam Mahdi
Keyword(s):  
Open Water ◽  
Rake Angle ◽  
Uniform Flow ◽  
Wake Flow ◽  
Hydrodynamic Performance ◽  
Experimental Result ◽  
Nonuniform Flow ◽  
Solution Scheme ◽  
Propeller Performance ◽  
Thrust And Torque

Marine propeller always operates in the wake of a vehicle (ship, torpedo, submarine) but (due to the high computational cost of simulating vehicle and propeller simultaneously) to investigate the propeller geometric parameters, simulations are usually performed in open-water conditions. In this article, using the computational fluid dynamics method with the control volume approach, the effect of the rake angle on the propeller performance and formation of cavitation in the uniform flow (open water) and the nonuniform flow (wake flow) was investigated. In the nonuniform condition, the array of plates was used to simulate wake at upstream propeller. For uniform flow, steady solution scheme was adopted and for nonuniform flow unsteady solution scheme was adopted, and a moving mesh zone was generated around the propeller. To simulate cavitation a multiphase mixture flow, the Reynolds-averaged Navier–Stokes method was used and modeled by Schnerr Sauer's cavitation model. First, the E779a propeller model for numerical validation in the uniform flow and nonuniform flow was investigated. Numerical results were compared with the experimental result, and there was a good agreement between volume of the cavity, thrust, and torque coefficients. To study the effect of rake angle on the performance of B-series propellers, four models with different rake angles were modeled, and simulation was investigated behind the wake. The results of thrust, torque coefficients, and cavitation volume according to the flow parameters and cavitation number were presented as graphs. The results reveals that in the uniform flow, the rake angle has no significant effect on the propeller performance, but behind the wake flow, increase of rake causes to reduce the force applied to the propeller blades, cavitation volume, and pressure fluctuations on the propeller.

Flow Field Analysis of Dielectrophoretically-Suspended Particles

2007 ◽  
Author(s):  
Stuart J. Williams ◽  
Steven T. Wereley
Keyword(s):  
Electric Fields ◽  
Particle Image ◽  
Fluid Velocity ◽  
Microfluidic Channel ◽  
Velocity Fields ◽  
Field Analysis ◽  
Tracer Particles ◽  
Image Velocimetry ◽  
Flow Field Analysis ◽  
Complete Investigation

Understanding the fluid dynamics around a particle in suspension is important for a complete investigation of many hydrodynamic phenomena, including microfluidic models. A novel tool that has been used to analyze fluid velocity fields in microfluidics is micro-resolution particle image velocimetry (μPIV) [1]. Dielectrophoresis (DEP) is a technique that can translate and trap particles by induced polarization in the presence of nonuniform electric fields. In this paper, DEP has been used to capture and suspend a single 10.1μm diameter spherical particle in a microfluidic channel. μPIV is then used with smaller tracer particles (0.5μm) to investigate the hydrodynamics of fluid flow past the trapped particle.

A New Methodology for Generation of Solitary Water Waves in Laboratory

2020 ◽  
Author(s):  
Xiao Liu ◽  
Yong Liu
Keyword(s):  
Solitary Wave ◽  
Wave Height ◽  
Water Waves ◽  
Particle Image ◽  
Fluid Velocity ◽  
Simple System ◽  
Wave Surface ◽  
Wave Flume ◽  
Image Velocimetry ◽  
Laboratory Flume

Abstract In this article, a very simple system based on the enhanced dam-break flows was proposed and implemented to generate solitary wave with larger relative wave height (the ratio of wave height to water depth) in a laboratory flume. The experimental results showed that stable waves with the solitary wave profiles were successfully generated in the wave flume. The wave surface elevations were recorded by a series of wave gauges, and the fluid velocity field of the solitary wave was measured by Particle Image Velocimetry (PIV) system. The measurements of solitary wave profile, celerity and horizontal fluid velocity were also compared with the predictions by three different solitary wave theories. Results demonstrated that the present simple system was reliable and effective for the generation of solitary waves in laboratory.

Direct measurement of fluid velocity in an electrospinning jet using particle image velocimetry

2007 ◽  
Vol 102 (9) ◽  
pp. 094308 ◽  
Author(s):  
Leon M. Bellan ◽  
Harold G. Craighead ◽  
Juan P. Hinestroza
Keyword(s):  
Particle Image Velocimetry ◽  
Direct Measurement ◽  
Particle Image ◽  
Fluid Velocity ◽  
Image Velocimetry

scholarly journals Numerical Investigation of the Hydrodynamic Performance of the Propeller Behind the Ship with and Without Wed

2020 ◽  
Vol 27 (4) ◽  
pp. 50-59
Author(s):  
Alireza Nadery ◽  
Hassan Ghassemi
Keyword(s):  
Pressure Pulse ◽  
Wake Flow ◽  
Hydrodynamic Performance ◽  
Analysis Software ◽  
Experiment Method ◽  
The Face ◽  
Computational Fluid Dynamics Cfd ◽  
Propeller Performance ◽  
Thrust And Torque ◽  
Face Side

AbstractThe presented paper numerically carries out the investigation of the hydrodynamic performance of the propeller behind the ship with and without wake equalizing duct (WED). It is mounted in front of the propeller in order to equalize the ship’s wake flow and improve the propeller performance. The computational fluid dynamics (CFD) analysis software STAR-CCM solver was adopted to simulate the KP505 propeller behind the KRISO container ship (KCS) using overlapping grid technology and user-defined functions. To obtain the effect of a –duct on propeller performance, the ship bare hull case, the with-propeller case, and the with-propeller-and-duct case are also computed. Together, these computations provide for a –complete CFD comparison of the duct effects. Also, the Taguchi design of the experiment method is applied to investigate three parameters (angle of attack, trailing edge radius, and chord length) of the duct. Finally, the main dimensions are obtained, and the thrust and torque coefficients are presented and discussed for one blade and whole blades during one cycle. Based on the numerical results, it is indicated that good design increases efficiency by 1.67%, and a –bad design may reduce efficiency by 3.25%. Also, the effect of the WED caused to decrease the pressure pulse by 35.9% in the face side of the propeller blade.

Experimental Measurements of Forces on Loose Particle in Motion Over Rough Bed Under Waves Using Oblique Particle Image Velocimetry

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Sanjay N. Havaldar ◽  
Francis C. K. Ting
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Fluid Layer ◽  
Fluid Velocity ◽  
Particle Diameter ◽  
Single Layer ◽  
Wave Direction ◽  
Loose Sediment ◽  
Image Velocimetry ◽  
Rough Bed

Magnitude and phase of major forces that act on a loose non-cohesive particle (sediment) on single layer fixed rough bed (longitudinal slope 2%) were determined from experiments in a laboratory flume under waves. The loose particles were glass spheres of diameter 1.58 ± 0.1 mm and specific gravity 2.5. The range of wave-height-to-water-depth (H/h) ratio in the experiments was 0.366 < H/h < 0.521. The measurement plane was parallel to the bed and located at a height of ½ loose particle diameter (ds) above the rough bed. Grayscale morphological image processing methods were used to separate the fluid and loose sediment phases from the same oblique particle image velocimetry (OPIV) image based on their signature sizes. The OPIV calibration method is presented and validated with conventional particle image velocimetry (PIV) method. Loose particle velocity and accelerations along with the associated fluid velocity and fluid total accelerations in the wave direction were determined simultaneously by processing OPIV used to compute magnitude and phase of major forces that act on the loose sediment particle. It was observed that for same wave period (T), an increase in H/h ratio has a dominant effect on sediment displacements onshore. The phase along with magnitude of the major driving force (drag and fluid accelerations) plays an important role at initiation of loose sediment from its rest position. It is suspected that the loose particle overcomes a critical bed friction force with higher H/h ratio as magnitude of drag force is higher. The resultant force then displaces the sediment onshore which experiences sliding and or rolling motions very close to bed, in a thin fluid layer over maximum protrusion of bed sediments. At the instance, the gravitational force plus bed frictions overcomes the lift force the loose particle attains a new position onshore.

Experimental Analysis of the Near Wake from a Ducted Thruster at True and Near Bollard Pull Conditions Using Stereo Particle Image Velocimetry (SPIV)

2005 ◽  
Vol 127 (3) ◽  
pp. 191-196 ◽  
Author(s):  
S. El Lababidy ◽  
N. Bose ◽  
P. Liu ◽  
D. Walker ◽  
F. Di Felice
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Practical Interest ◽  
Stereoscopic Particle Image Velocimetry ◽  
Wake Flow ◽  
Hydrodynamic Characteristics ◽  
Near Wake ◽  
Image Velocimetry ◽  
Wide Range ◽  
Marine Applications

Thrusters working at low advance coefficients are employed in a wide range of offshore and marine applications on Floating, Production, Storage, and Offloading (FPSO) systems; shuttle tankers; tug boats; and mobile offshore units. Therefore, an understanding of the flow around the thrusters is of great practical interest. Despite this interest, there is lack of knowledge in the description of the hydrodynamic characteristics of a ducted thruster’s wake at bollard pull and low advance coefficient values. This work was aimed at providing detailed data about the hydrodynamic characteristics of a Dynamic Positioning (DP) thruster near wake flow at different low advance coefficient values. Wake measurements were made during cavitation tunnel tests carried out on a ducted propeller model at the Italian Ship Model Basin (INSEAN), Rome, Italy. Through these experiments, the DP thruster near wake velocity components at different downstream axial planes, up to 1.5 diameters downstream, were obtained using a Stereoscopic Particle Image Velocimetry (SPIV) system. These experiments were carried out at different advance coefficient (J) values [bollard pull (J=0), J=0.4 and J=0.45].

Stereo three-dimensional particle image velocimetry measurement and aerodynamic force analysis of non-spinning soccer balls

2020 ◽  
Vol 234 (2) ◽  
pp. 146-153 ◽  
Author(s):  
Masaki Hiratsuka ◽  
Shinichiro Ito ◽  
Keita Miyasaka ◽  
Akihisa Konno
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Jet Flow ◽  
Flight Path ◽  
Wake Flow ◽  
Force Measurements ◽  
Flow Measurements ◽  
Image Velocimetry

A knuckle shot, resulting from non-spinning kicking, is an essential technique in soccer. The irregular flight path of the knuckle shot is caused by the aerodynamic force from the three-dimensional twin vortices generated in the wake behind the ball. However, the detailed behavior of the twin vortices and relation between the jet flow and the acting forces on the balls is still not understood. In addition, a more thorough understanding of the effect of ball panels on the formation of twin vortices and jet flow is important to develop balls with high controllability. To study the effect of the ball panel shape on the flight path, stereo three-dimensional particle image velocimetry wake flow measurements and synchronized force measurements were performed on various soccer balls. It was confirmed that the aerodynamic force on the ball is produced by the jet flow generated by the vortices in the wake flow. The directions of the force followed the changes of the jet flow, and the magnitude of the force was strongly associated with the flow rate of the jet. Moreover, the shape of the ball panels, especially the groove volume, determines the critical Reynolds number and the fluttering of the balls.

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