scholarly journals Effect of Gait and Turn Direction on Body Lean Angle in the Horse

2014 ◽  
Vol 46 ◽  
pp. 36-37 ◽  
Author(s):  
C Brocklehurst ◽  
R Weller ◽  
T Pfau
Keyword(s):  
Lean Angle ◽  
Turn Direction

Effect of turn direction on body lean angle in the horse in trot and canter

2014 ◽  
Vol 199 (2) ◽  
pp. 258-262 ◽  
Author(s):  
C. Brocklehurst ◽  
R. Weller ◽  
T. Pfau
Keyword(s):  
Lean Angle ◽  
Turn Direction

scholarly journals The effect of curve running on distal limb kinematics in the Thoroughbred racehorse

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244105
Author(s):  
Rebecca S. V. Parkes ◽  
Thilo Pfau ◽  
Renate Weller ◽  
Thomas H. Witte
Keyword(s):  
Calculated Data ◽  
Measurement Unit ◽  
Large Radius ◽  
Accelerometer Data ◽  
Functional Requirements ◽  
Distal Limb ◽  
Centripetal Acceleration ◽  
Significance Level ◽  
Thoroughbred Horses ◽  
Lean Angle

During racing, injury is more likely to occur on a bend than on a straight segment of track. This study aimed to quantify the effects of galloping at training speeds on large radius curves on stride parameters and limb lean angle in order to assess estimated consequences for limb loading. Seven Thoroughbred horses were equipped with a sacrum-mounted inertial measurement unit with an integrated GPS, two hoof-mounted accelerometers and retro-reflective markers on the forelimbs. Horses galloped 2–4 circuits anticlockwise around an oval track and were filmed at 120 frames per second using an array of ten cameras. Speed and curve radius were derived from GPS data and used to estimate the centripetal acceleration necessary to navigate the curve. Stride, stance and swing durations and duty factor (DF) were derived from accelerometer data. Limb markers were tracked and whole limb and third metacarpus (MCIII) angles were calculated. Data were analysed using mixed effects models with a significance level of p < 0.05. For horses galloping on the correct lead, DF was higher for the inside (lead) leg on the straight and on the curve. For horses galloping on the incorrect lead, there was no difference in DF between inside and outside legs on the straight or on the curve. DF decreased by 0.61% of DF with each 1 m s-2 increase in centripetal acceleration (p < 0.001). Whole limb inclination angle increased by 1.5° per 1 m s-1 increase in speed (p = 0.002). Limb lean angles increase as predicted, and lead limb function mirrors the functional requirements for curve running. A more comprehensive understanding of the effects of lean and torque on the distal limb is required to understand injury mechanisms.

Effects of Blade Stack on Pipeline Compressor Impeller Performance

2008 ◽  
Author(s):  
Michael J. Cave
Keyword(s):  
Natural Gas ◽  
Gas Pipeline ◽  
Cfd Analysis ◽  
Natural Gas Pipeline ◽  
Back Testing ◽  
Compressor Impeller ◽  
Lean Angle ◽  
Experimental Rig ◽  
Probe Measurements ◽  
Blade Geometry

Back to back testing of two centrifugal gas compressors used for natural gas pipeline transmission applications were completed. Blade geometry is very similar with the exception of stack of the impeller mean camber-lines. This resulted in significantly different lean angle distributions and rake at the exit of the two impellers. Both impellers performed exceptionally well in terms of efficiency and range, but with a marked difference in head making capability. CFD analysis using CFX-TASCflow was conducted to identify the underlying cause for the change in head. The CFD analysis was then validated using an experimental rig impeller that included traverse probe measurements at the pinch exit. Once the CFD was validated, a discussion is included on how to apply the knowledge learned to future impeller designs.

Compensation of Intake Induced Flow Non-Uniformities With Compressor Blade Lean Angle Changes

2009 ◽  
Author(s):  
Ioannis Templalexis ◽  
Vassilios Pachidis ◽  
Petros Kotsiopoulos
Keyword(s):  
Gas Turbine ◽  
Flow Simulation ◽  
Gas Turbine Engine ◽  
Compressor Blade ◽  
Design Stage ◽  
Computational Time ◽  
Turbine Engine ◽  
Lean Angle ◽  
Compressor Performance ◽  
Induced Flow

The compression system has traditionally drawn most of the attention concerning the gas turbine engine performance assessment and design procedure. It is the most vulnerable component to flow fluctuations within a gas turbine engine. In particular this study focuses on performance deviations, between an installed and an uninstalled compressor. Test results acquired from a test bed installation will differ from these recorded when the compressor operates as an integral part of the engine. The upstream duct, whether an intake or an interstage duct, will affect the flow field pattern ingested into the compressor. The case studies presented into this work aim to mostly qualify the effect of boundary layer growth along the upstream duct walls, upon compressor performance. Additionally, compressor performance response on blade lean angle variation is being addressed, with the aim of acquiring an understanding as to how compressor blade lean angle changes interact with intake induced flow non uniformities. Such studies are usually conducted during the preliminary design stage, before the compressor is built. Consequently, experimental performance investigation is excluded at this stage of development. Computer aided simulation techniques are between the few if not the only option for compressor performance prediction. Given the fact that many such design parameters need to be assessed under the time pressure exerted by the tight compressor development program, the compressor flow simulation technique used needs to provide reliable results while consuming the least possible computational time. Such a low computational time compressor flow simulation method, among others, is the two dimensional (2D) streamline curvature (SLC) method, being applied within the frame of reference of the current study. The paper is introduced by a brief discussion on SLC method that was proposed more than 50 years ago. Then a reference is made to the Radial Equilibrium Equation (REE) which is the mathematical basis of the code, commenting on the assumptions that were undertaken. Subsequently the influence of the intake presence on the compressor inlet radial flow distribution is being addressed, with the aim of adjusting compressor blade inlet lean angle, in order to minimize compressor performance deterioration. Finally the paper is concluded with a discussion of the results.

The Effect of Blade Lean on the Solution of the Full Radial Equilibrium Equation

2008 ◽  
Author(s):  
Ioannis Templalexis ◽  
Vassilios Pachidis ◽  
Pericles Pilidis ◽  
Petros Kotsiopoulos
Keyword(s):  
Equilibrium Equation ◽  
Axial Flow ◽  
Design Tool ◽  
Convergence Time ◽  
Extensive Literature ◽  
Two Dimensional ◽  
Computational Power ◽  
Through Flow ◽  
Lean Angle ◽  
Radial Equilibrium

Taking into account the increasing availability of computational power at an affordable cost, two-dimensional through-flow calculation methods are gaining more and more attention, given the fact that the required time for convergence is continuously reducing. Consequently, several application fields (i.e. whole engine performance simulation), that were traditionally dominated by simpler and faster zero-dimensional or one-dimensional methods, purely because of computational power restrictions, gradually move towards two-dimensional analyses. These tend to offer more information about the flow-field at a greater accuracy. The Radial Equilibrium Equation (REE), in its either simple or full version, has been the basis of several two-dimensional and quasi-three-dimensional through-flow techniques that are being used for the flow analysis within ducts, compressors and turbines. The aim of this paper is to provoke a thorough discussion on the actual solution of the full REE for the determination of the meridional velocity profile. More precisely, this manuscript discusses in detail the implications on the solution of the full REE when the blade lean angle related terms are included in the equation. This issue has only been superficially addressed in the existing literature up to this stage. The expressions for radial equilibrium addressed in the context of this paper, mainly consist the basis of a particular streamline curvature code (2D SLC Compressor Software), developed as a performance investigation and design tool of axial flow compressors. This code has been through a number of ‘improvement cycles’ over its several years of existence. One such cycle included the elaborate study of several final versions of the full REE, in order to reassure a stable and fast convergence for the final solution, while maintaining the highest possible level of accuracy. Firstly, this manuscript presents the final version of the full REE, commenting on each individual term in the equation, as well as on the various assumptions made during its derivation process. The two different solutions of the equation are given for zero and non-zero blade lean angle values. Moreover, the implications of the solution of the non-zero blade lean angle equation on the stability, convergence time and accuracy of the final results are pointed out. Finally, some conclusions are expressed as far as the effects of the blade lean angle on a compressor blade row performance and the actual applicability of the two forms of the REE are concerned. These conclusions were drawn from personal experience applying the equations but also from an extensive literature review conducted.

The Effect of Turbulator Lean on Heat Transfer and Friction in a Square Channel

2003 ◽  
Author(s):  
Ronald S. Bunker ◽  
Sarah J. Osgood
Keyword(s):  
Heat Transfer ◽  
Flow Direction ◽  
Standard Form ◽  
Bulk Flow ◽  
Transfer Coefficients ◽  
Square Channel ◽  
Heat Transfer Coefficients ◽  
Friction Factors ◽  
Lean Angle ◽  
Series Of Experiments

An experimental study has been performed to investigate the convective heat transfer coefficients and friction factors present in square cooling passages with non-normal, or leaned turbulators. The standard form of turbulated channels used in virtually all turbine vanes and blades is that of nearly square turbulators, or rib rougheners, cast in an orthogonal orientation to the channel surface. While turbulators may be oriented at an angle to the bulk flow direction, the projection of the turbulator is still normal to the cast surface. Non-orthogonal lean angle presents an additional variable which may be used to improve or optimize performance, a factor hitherto not investigated. The present study has performed a series of experiments measuring both detailed heat transfer coefficient distributions and friction factors within a square channel with flow Reynolds numbers up to 400,000. Turbulator lean angles of 45, 22.5, 0, −22.5, and −45-degrees to the surface normal have been tested with a turbulator configuration of 45-degree orientation to the bulk flow, pitch-to-height ratio of 10, and height-to-hydraulic diameter ratio of 0.1. Results show up to a 20% reduction in heat transfer capability, and as much as 30% increase in friction factor. The local distributions of heat transfer are also more variable with lean angle. The conclusion is made that normal turbulators provide the best overall performance.

scholarly journals KINEMATICAL STRATEGY TO REGAIN BALANCE DURING A FORWARD FALL ON A SLIPPERY FLOOR

2001 ◽  
Vol 13 (01) ◽  
pp. 27-32 ◽  
Author(s):  
PEI-HSI CHOU ◽  
YOU-LI CHOU ◽  
SHANG-LIN LEE ◽  
JIA-YUAN YOU ◽  
FONG-CHIN SU ◽  
...  
Keyword(s):  
Response Time ◽  
Horizontal Plane ◽  
Step Length ◽  
Human Walking ◽  
Motion Analysis System ◽  
Related Factors ◽  
Lean Angle ◽  
Foot Strike ◽  
Analysis System ◽  
Biomechanical Factors

Slips and falls often occur in the industrial environments. They are not only caused by environmental hazards but also by some biomechanical factors related to deficient ability of postural control to arrest impending falls. The purpose of this study is to simulate the slip condition in human walking and to find out the possible related factors of biomechanics. Eleven male and 9 female recruited were healthful without any musculoskeletal and neurological impairments. In order to provide different disturbance level, three lean angles of tilting boards were designed as 10, 20, 30 degrees with respect to horizontal plane. Subjects wore a safety harness, stood on the tilting board and were released without awareness. A forceplate applied a soap patch was in front of the tilting board to serve the slippery perturbation and to measure the fool/floor reactions. Movements of body segments were measured using the motion analysis system. The results were shown that lean angle had a significant effect to all parameters except step length, response time, maximum ankle forward velocity, hip forward velocity, and ankle flex angle. The gender significantly affected on the step length, response time, maximum ankle forward velocity, and knee forward velocity. Larger lean angle made subjects to take a more rapid step. In order to absorb the shock in foot strike, subjects flexed more their knee and increased the foot landing angle in larger lean angle. Male tended to adopt the long step-length strategy to respond to the slippery perturbation and female tended to use the short step-length strategy instead. The results of maximum ankle forward velocity suggested that short step-length strategy could be belter to reduce the foot slip than long step-length strategy.

Coupled Numerical Simulation of Process in Rheocasting-Rolling for Semi-Solid Magnesium Alloy Used By Slope

2010 ◽  
Vol 89-91 ◽  
pp. 681-686 ◽  
Author(s):  
Ying Zhang ◽  
Shui Sheng Xie ◽  
Mao Peng Geng ◽  
Hong Min Guo ◽  
Hai Bo Zhao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Magnesium Alloy ◽  
Technical Parameter ◽  
The Finite Element Method ◽  
Pouring Temperature ◽  
Flow And Heat Transfer ◽  
Lean Angle ◽  
Semi Solid ◽  
Energy Equations

By the finite element method, the N-S momentum, energy equations and continuum equations, etc. which describe the fluid flow and heat transfer in the slope of the rheocasting-rolling for Semi-solid Magnesium Alloy were computed. The influence of the different slope parameters( pouring temperature, length of slope, lean angle)on the metallographic structure of semi-solid magnesium alloy was analyzed. The simulative results can provide effective data to confirm optimized slope size and technical parameter.

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