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Analysis of nozzle orifice size effect on smoke in a diesel engine
AuthorsM Ishida ; D Sakaguchi ; H Ueki
Date published2000
AbstractThe effect of nozzle orifice size on smoke emission was examined in a turbo charged DI diesel engine. The nozzle orifice size was varied under various engine conditions. The rates of emissions were analysed. The results showed that the soot particle size was dependent on the orifice size and also on the spray penetration for the ignition delay period for the ignition delay period. The number of soot particles was shown to be dependent on the amount of fuel injected and on the excess air ration of the burned zone.
AuthorsM Ishida ; D Sakaguchi ; H Ueki
Date published2000
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Effect of truncated demand and capacity distributions on reliability of pipelines
AuthorsZiad Nakat ; Robert Bea
Date published2003
AbstractThis paper describes the effect of truncations on the reliability of pipelines. The effect of truncation by relief valves on the demand distribution is studied first. The effect of truncation by hydro-testing on the capacity distribution is studied second. Lastly the combined effect of truncation on demand and capacity is studied. A comparison and analysis of results is presented to assess the importance of truncated distributions of demand and capacity on the reliability of pipelines.
AuthorsZiad Nakat ; Robert Bea
Date published2003
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Effects of compression rate on unconfined compressive strength of cohesive soils - evaluation based on the effective stress
AuthorsM Shimizu
Date published1997
AbstractThe effects of the compression rate on the unconfined compressive strength are studied from the viewpoint that the strength needs to reflect the effective stresses of samples. Unconfined compression tests are performed on two remolded and consolidated clays of high and low plasticity index values with the measurement of pore water pressure via the pressure plate technique. A look is taken at the samples and method. Lastly the results are discussed.
AuthorsM Shimizu
Date published1997
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Effects of drained pre-loading on the performance of shallow foundations on over-consolidated clay
AuthorsB M Lehane ; C Gaudin
Date published2005
AbstractThis paper presents results from a programme of centrifuge experiments which examined the effects of drained pre-loading on the stiffness and load carrying capacity of shallow square footings founded on an over-consolidated clay. The increases in stiffness and bearing capacity induced by various levels of pre-loading are quantified and compared with standard design guidelines and previously published numerical predictions.
AuthorsB M Lehane ; C Gaudin
Date published2005
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The effect on installation on the pullout capacity of ground anchor
AuthorsI Zakaria
Date published2000
AbstractThe objective of this investigation is to evaluate the effect of disturbance set up during installation on the pullout capacity of a ground anchor. Investigations show that the test results in homogeneous sands beds is consistent with previous theories. For an anchor embedded in a disturbed zone its breakout factor is also dependent on the ratio of depth/diameter of the anchor. The ultimate resistance of this anchor is significantly reduced when the ratio of depth/diameter exceeds 3. However the effect is not apparent when the width of the disturbed zone is equal to or more than three times the anchor diameter.
AuthorsI Zakaria
Date published2000
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The influence of slamming and whipping on the fatigue life of a high-speed catamaran
AuthorsGiles Thomas ; Michael Davis ; Damien Holloway et al.
Date published2005
AbstractThis paper reports on an investigation into the influence of slamming and whipping on the fatigue life of a large high-speed catamaran. Full-scale measurements of slam events were conducted on a 98m Incat catamaran to investigate its slamming behaviour in a variety of sea conditions. The full scale results were then used to determine the influence of the presence of slam events on fatigue life. In addition the effects of significant wave height slam occurrence rates slam peak stresses and whipping behaviour on fatigue life were examined.
AuthorsGiles Thomas ; Michael Davis ; Damien Holloway et al.
Date published2005
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Current forces on a large pier near an existing pier
AuthorsSubrata K Chakrabarti ; Mark McBride
Date published2004
AbstractA new suspension bridge is being built over the Tacoma Narrows Washington. The bridge will be placed on a structure mounted on 2 large concrete caissons which will be exposed to strong currents. The caissons are being built at site while floating and moored in high currents. In order to determine the forces on the caisson due to current a series of scaled physical model tests of one of the caissons was carried out. The forces on the new caisson were measured in the presence of the existing bridge pier and the bottom contours of the Narrows were accurately modeled. The model scale was chosen as 1:100 and the tests were performed for the caisson at different drafts. This paper describes the test setup and measurement system for a series of fixed caisson tests and demonstrates the consistency of the test data. The measured inline drag and transverse lift forces on the fixed caisson at different drafts are presented and the effect of the fluid velocity and flow vorticity on the frequency contents in the forces is discussed. The interaction effect of the neighbouring existing pier on the current forces of the new caisson is investigated. Since the measured forces were applied in the design analysis of the caissons the scaling effect of the model test is also discussed.
AuthorsSubrata K Chakrabarti ; Mark McBride
Date published2004
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Numerical analysis on added resistance of ship by 3D Green Function Method
AuthorsYoshiyuki Inoue ; N M Golam Zakaria
Date published2005
AbstractIn the present competitive market undertaking a ship mission on schedule and on time is important. Predicting increased resistance of a ship to her governing wave climate is therefore important. At present there are several methods available for dealing with the problem of resistance increase in waves. Most of these methods are based on the calculation of motion responses by Strip Theory or Slender Ship Theory. Although these methods are easy to use and produce acceptable results some of their shortcomings (due to the neglect of 3D hydrodynamic effect) make them unable to provide enough estimation of the increase of resistance in waves especially for fuller ship form vessels. The 3D Green function method with forward speed is now able to estimate better all relevant hydrodynamic responses and is therefore becoming increasingly popular. Linear potential theory is used to describe the fluid motion. The 3D sink-source technique with forward speed is applied to determine hydrodynamic forces for surface ship advancing in waves at constant speed. After solving the motion equation in frequency domain radiation potential due to motion responses is calculated to obtain the total potential of the flow field. Then total potential and its derivatives are obtained to assess the added resistance in waves by near field approach. To show the validity of the numerical code the present numerical results for motion responses and wave loads on ships are compared with experimental data as well as with some numerical results achieved by different approaches. Next the added resistances given by present numerical calculation byX38576 A numerical analysis on the deformation of decomposed granite soil foundation using elasto-plastic model
AuthorsYoshiyuki Inoue ; N M Golam Zakaria
Date published2005
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Scaling for performance prediction in rotor dynamic machines
AuthorsIMechE
PublisherIMechE
AbstractConf held in London on 6 - 8 September 1977 Papers are Statistical records of pump and water turbine efficiencies Cavitation breakdown of an axial flow pump operating in water having a dilute polymer concentration Water turbine scale effects and efficiency majoration methods The performance of pumps and fans at peak efficiency Scaling of cross flow fans - an experimental comparison Basic and applied aspects of scaling cavitation noise Scale model performance testing to assess the effect of a foundation transverse rocking vibration mode on centrifugal industrial fan shafts Cooling performance evaluation of turbine blades and nozzle guide vanes by scaled testing at other than engine conditions Installation effects on wet well pump performance The performance prediction of scaled axial compressors from model tests Predictive capability for cavitation damage from bubble collapse pulse count spectra Polytropic processes in the performance prediction of centrifugal compressors Scale effect on performance parameters of axial flow fans and pumps Determination of individual losses and scale effect by model tests with a radial pump The influence of scaling on the performance of small centrifugal compressors The effect of size and speed on measured pump cavitation performance Further studies of scaling laws governing cavitation erosion Specific speed as a measure design point efficiency and optimum geometry for a class of compressible flow turbo machines On site efficiency tests on reversible pump turbines at the Scottish Cruachan and Foyers pumped storage plants
AuthorsDate publishedIMechE
1977
PublisherIMechE
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2nd International Conference on Cavitation
AuthorsIMechEng
Shelf Location225d
AbstractSecond Int conf held in Edinburgh 5 - 8 September 1983 Papers are A study of cavitation bubble dynamics and resultant pressure on adjacent solid boundaries Cavity dynamics in a duct flow A study of the relationship between type of cavitation erosion and luminescence Bubble dynamics and cavitation Some recent aspects of bubble dynamics Classification of cavity mechanics and erosion Effects of magnetic field on cavitation damage A modelling study of the cavitation microjet Measurement of cavitation erosion in a centrifugal pump as a function of speed Cavitation in a binary mixture of polar liquids Studies on the cavitation characteristics of annular type jet pump Effect of inlet diameter of mixed flow impellers on suction performance On cavitation in stationary cascades of reversible hydraulic machines The calculation of three dimensional flows in impellers and its use in improving the cavitation performance of centrifugal pumps Cavitation signs in rotodynamic pump Recent and expected technological advancement towards the elimination of cavitation damage in control waves Vapour cavitation in dynamically loaded journal bearings Further studies of propeller cavitation erosion Effects of artificial roughness on sheet cavitation On application of nonlinear cavity flow theory to thick foil sections
AuthorsPublisherIMechEng
IMechEng
Shelf LocationDate published225d
1983
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A research on characteristics of responses of a floating structure in tsunami
AuthorsKoichi Masuda ; Tomoki Ikoma ; Maki Uchida et al.
Date published2004
AbstractThe objective of this paper is to establish the practical numerical analysis system for responses of motions and mooring forces on a floating structure induced by Tsunami and to clarify the characteristics of responses on floating bodies in tsunami. In the present analysis system the initial tsunami profile is evaluated by Mansinha-Smylie's Method and propagating tsunami profiles are calculated by linear long wave theory and also the tsunami exciting forces on floating body are computed by the numerical wave tank based on VOF method. Then the motions and mooring tether forces due to Tsunami on floating body are predicted by the convolution integral method. The usefulness of the present system is confirmed by comparing with the experimental results on Tsunami exciting forces on floating bodies.
AuthorsKoichi Masuda ; Tomoki Ikoma ; Maki Uchida et al.
Date published2004
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A theoretical study on the effect of seaquakes on a two-dimensional floating body
AuthorsY Higo
Date published1997
AbstractA reasonable numerical calculation method of seismic wave propagation in two-layered medium is presented. The hydrodynamic pressure caused by seaquake is analyzed numerically and its dynamic effects on the floating structure is investigated. First some background information is given. Next a look is taken at the problem formulation. After this the numerical results are discussed.
AuthorsY Higo
Date published1997
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Effect of principal stress direction on undrained cyclic shear behaviour of dense sand
AuthorsKen-ichi Sato ; Nobuo Yoshida
Date published1999
AbstractA series of undrained cyclic torsional shear tests using dense sand specimens with bedding planes have been conducted to investigate the effect of initial fabric anisotropy on liquefaction characteristics. After some introductory information attention is given to the test procedures. Next a look is taken at the effect of cyclic stress ratio on cyclic shear characteristics followed by the effect of principal stress direction on undrained cyclic shear characteristics. Lastly consideration is given to the effect of principal stress direction on cyclic shear strength.
AuthorsKen-ichi Sato ; Nobuo Yoshida
Date published1999
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Hydrodynamic force on a wall due to breaking waves
AuthorsJ-J Shu ; A T Chwang
Date published2000
AbstractThis paper studies the impact forces of breaking waves on a rigid wall based on a nonlinear potential-flow theory. This is a model problem for some technologically important design issues such as the impact of breaking waves on ships coastal and offshore structures. We are interested in the short time successive triggering of nonlinear effects using a small-time expansion. The analytical solutions for the impact force on a rigid wall and the free-surface profile are derived.
AuthorsJ-J Shu ; A T Chwang
Date published2000
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Hydrodynamic loading of compact structures and the effect on foundation design
AuthorsA R Henderson ; M B Zaaijer
Date published2002
AbstractAttention is given to various methods to calculate wave loading on compact structures and the effect of hydrodynamic loading on the foundation design solution based on a case study of a 3 MW turbine at a Baltic site. After some introductory information a look is taken at hydrodynamic loading. Next resistance factors are considered followed by load and resistance factor analysis. Effects of hydrodynamic modelling on design solution are dealt with and recommendations are made.
AuthorsA R Henderson ; M B Zaaijer
Date published2002
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Impact on emission legislation on large engine design and operation Publication 475
AuthorsH Niven
Date published1992
AbstractDiesel engines achieve the best thermal efficiency of any prime mover. The high efficiency of the diesel engine is a result of high cylinder pressures used which creates high temperatures that burn hydrocarbon fuels used. The resultant combustion process is very clean. This paper describes the constituents of diesel engine exhaust its effect on the environment and the reduction strategies employed at present to meet stringent emission levels.
AuthorsH Niven
Date published1992
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Irregular broken wave forces on vertical wall
AuthorsY-C Li ; D-z Liu ; G-p Qi et al.
Date published1997
AbstractA technique to calculate total horizontal wave forces by irregular broken waves on vertical wall has been developed. This is based on physical model test dimensionless analysis and assessment of real construction. Also the method to determine pressure distribution of horizontal forces on vertical wall in addition to uplift forces on the bottom of the wall is recommended. There is fairly good agreement between the results calculated by this method and real construction.
AuthorsY-C Li ; D-z Liu ; G-p Qi et al.
Date published1997
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Numerical study on breaking indices for solitary wave on slopes
AuthorsC R Chou
Date published2001
AbstractThe shoaling and breaking of solitary waves propagating on various types of mild slope is investigated. The breaking criterion of these waves is studied using the boundary element method. Suggestions of breaking indices for slopes 1:10 to 1:50 are given. The deformation of wave profiles as well as the distribution of fluid velocities at the breaking region for slopes 1:30 to 1:50 are shown. The classification of surging breakers and spilling breakers is explained.
AuthorsC R Chou
Date published2001
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on relation between flow behaviour and the lateral force distribution acting on a ship in oblique motion
AuthorsBart van Oers ; Serge Toxopeus
Date published2006
AbstractThis paper presents the results of a research project focussed on the simulation of the viscous flow fields around five vessels sailing at a non-zero drift angle. The calculated flow fields were used to investigate flow features relevant to the lateral-force distribution thus offering insight in the physics involved in the manoeuvring behaviour of ships. This insight can be used to improve the manoeuvring characteristics in the early stages of the design process.
AuthorsBart van Oers ; Serge Toxopeus
Date published2006
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Study on stern tube sealing system (blister of sealing ring)
AuthorsS Yamajo
Date published1983
AbstractThe failure of stern tub sealing systems due to blister formation on the lip ring seal was investigated by - observations on the occurance of blisters in conventional and improved type sealing rings analysis of their contents structure and material homogenity; and by laboratory studies on conditions (temperature pressure eccentricity speed environment) affecting the formation of blisters on test pieces (nitrile-butadiene rubber and fluorocarbo rubber) in simulated service conditions. Results are used to propose a mechanism of blister formation and to discuss preventive measures.
AuthorsS Yamajo
Date published1983