Theory of High-Speed Displacement Ships with Transom Sterns

1986 ◽  
Vol 30 (03) ◽  
pp. 186-193
Author(s):  
Marshall P. Tulin ◽  
C. C. Hsu
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Parametric Form ◽  
High Speeds ◽  
New Finding ◽  
Good Agreement

A theory has been developed for high-speed displacement ships with transom sterns; it treats the hull as finite in beam and draft, but slender. The flow is assumed to be smooth at the aft waterline and to have a trailing wake. The trailing wake results in substantial residuary resistance at high speeds for normal waterline ships. This is a completely new finding. Calculations are made for ships of highly variable parametric form and the results are given. This residuary is typically reduced by widening the transom. A shallow draft at the transom is also indicated. A comparison of calculated results with existing experimental data shows good agreement.

Stability of Water-Lubricated, Hydrostatic, Conical Bearings With Spiral Grooves for High-Speed Spindles

2001 ◽  
Vol 124 (2) ◽  
pp. 398-405 ◽  
Author(s):  
S. Yoshimoto ◽  
S. Oshima ◽  
S. Danbara ◽  
T. Shitara
Keyword(s):  
High Speed ◽  
Water Pressure ◽  
Rotating Shaft ◽  
Pressurized Water ◽  
High Speeds ◽  
Theoretical Predictions ◽  
The Stability ◽  
Stability Of Water ◽  
Spiral Grooves ◽  
Good Agreement

In this paper, the stability of water-lubricated, hydrostatic, conical bearings with spiral grooves for high-speed spindles is investigated theoretically and experimentally. In these bearing types, pressurized water is first fed to the inside of the rotating shaft and then introduced into spiral grooves through feeding holes located at one end of each spiral groove. Therefore, water pressure is increased due to the effect of the centrifugal force at the outlets of the feeding holes, which results from shaft rotation. In addition, water pressure is also increased by the viscous pumping effect of the spiral grooves. The stability of the proposed bearing is theoretically predicted using the perturbation method, and calculated results are compared with experimental results. It was consequently found that the proposed bearing is very stable at high speeds and theoretical predictions show good agreement with experimental data.

Performance Calculation of a TBD234V12 Diesel Engine with STC

2012 ◽  
Vol 157-158 ◽  
pp. 1075-1078
Author(s):  
Yang Wang ◽  
Yin Yan Wang ◽  
Fan Shi ◽  
Xin Guang Li
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Computer Model ◽  
High Speed ◽  
Marine Diesel Engine ◽  
High Speed Diesel ◽  
Turbocharging System ◽  
Marine Diesel ◽  
Performance Calculation ◽  
Good Agreement

A computer model for a TBD234V12 marine high-speed diesel engine with 2 turbocharger(2TC) is built on GT-POWER. For validating the computer model, a calculation to the conventional turbocharging system has been done firstly, and the results show good agreement with experimental data. The computer model has then been used for predictive studies of the diesel engine with the proposed STC system on the mapping characteristics. From these results, it can be seen that the STC system can not only improve the part load performance of the diesel engine obviously, but also enlarge the operating range of the marine diesel engine.

Dynamics of Rolling Element—Bearings Experimental Validation of the DREB and RAPIDREB Computer Programs

1985 ◽  
Vol 107 (1) ◽  
pp. 132-137 ◽  
Author(s):  
P. K. Gupta ◽  
J. F. Dill ◽  
H. E. Bandow
Keyword(s):  
Experimental Data ◽  
Experimental Validation ◽  
Ball Bearing ◽  
Rolling Element Bearings ◽  
Mass Center ◽  
Angular Contact Ball Bearing ◽  
High Speeds ◽  
Rolling Element ◽  
General Motion ◽  
Good Agreement

The general motion of the cage predicted by the computer models in an angular contact ball bearing operating up to two million DN is compared against experimental data. Both the computer predictions and experimental data indicate a certain critical shaft speed at which the cage mass center begins to whirl. The predicted and measured whirl velocities and orbit shapes are in good agreement. The axial and radial velocities of the cage mass center also agree within the tolerance band of the expected experimental error. Due to experimental difficulties the cage angular velocity could not be reliabily measured at high speeds. At low speeds, however, there is a fair agreement between the experimental data and the analytical predictions.

scholarly journals Experimental and Numerical Investigation of Stepped Planing Hulls in Finding an Optimized Step Location and Analysis of Its Porpoising Phenomenon

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Sayyed Mahdi Sajedi ◽  
Parviz Ghadimi
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Three Dimensional ◽  
Single Step ◽  
Hydrodynamic Resistance ◽  
Resistance Reduction ◽  
Step Model ◽  
Volume Method ◽  
Mesh Technique ◽  
Good Agreement

Stability of a high-speed craft is an essential matter, and porpoising is one of the most critical instabilities that could occur in some planing hulls due to inappropriate design. In this paper, the porpoising phenomenon and variation of step location yielding resistance reduction are studied through experimental and numerical methods. The investigated models include a single-step model and a nonstep model with the same general shape, but with different step location. The nonstep model is previously tested, but the single-step model is examined in the present study. The nonstep model experiences porpoising at 8 m/s speed, but the single-step model remains stable at the same speed. A three-dimensional CFD analysis is conducted using the finite volume method (FVM). On the contrary, the volume of fluid (VOF) scheme is used for free surface modeling, and the overset mesh technique is implemented within StarCCM+ software. The CFD results of total hydrodynamic resistance and dynamic trim angle are compared against the experimental data. The numerical results are in good agreement with the experimental data. Subsequently, ten different stepped models are simulated to examine their effects. The longitudinal distance between steps and aft of these models are in the range of 19 to 50 percent of the length of models. The obtained results show that as steps are located farther than aft, the models become more stable, and resistance increases due to trim reduction. Finally, the optimum location of the step is extracted with the aim of minimizing the resistance through the design of experiment (DOE) method. Based on the DOE method, it is observed that the sensitivity of the drag value to the step location is higher than the speed.

A study of the slipstreams of high-speed passenger trains and freight trains

2008 ◽  
Vol 222 (2) ◽  
pp. 177-193 ◽  
Author(s):  
M Sterling ◽  
C J Baker ◽  
S C Jordan ◽  
T Johnson
Keyword(s):  
Experimental Data ◽  
Boundary Layers ◽  
High Speed ◽  
Flow Characteristics ◽  
Full Scale ◽  
Small Scale ◽  
Flow Features ◽  
Passenger Trains ◽  
Container Freight ◽  
Good Agreement

As the speeds of both passenger and freight trains increase, there is increasing concern that the unsteady gusts generated in train boundary layers and wakes will become more of for a risk to passengers waiting on platforms and for trackside workers. In addition, the demands of interoperability make this a problem of growing relevance to railway operators across Europe. A number of model scale and full-scale experiments have been carried out in recent years that have provided robust experimental data to quantify these flows. This paper considers all the available datasets for high-speed passenger trains and container freight trains, and in making a comparison between them, arrives at a number of conclusions concerning the characteristics of train slipstreams. It is concluded that the identification of a number of distinct flow regions in earlier work is generally valid and forms a useful framework for the consideration of the problem. The flow characteristics are different in each region, and, depending upon the train type, the measurement distance from the train and height above ground, the observed peak gusts for a train may occur at any time during the train passage or in its wake. It is also concluded that results obtained from measurements around small scale moving models are in good agreement with the full scale measurements and reproduce all the important flow features.

An Investigation of the Different Flow Regimes in a Rotating Drum through Experimental and Simulation

2014 ◽  
Vol 802 ◽  
pp. 215-219
Author(s):  
D.A. Santos ◽  
Irineu Petri Jr. ◽  
C.R. Duarte ◽  
M.A.S. Barrozo
Keyword(s):  
Experimental Data ◽  
Particle Velocity ◽  
High Speed ◽  
Video Camera ◽  
Particle Dynamic ◽  
Multiphase Model ◽  
Rotating Drum ◽  
High Speed Video Camera ◽  
Simulation Results ◽  
Good Agreement

This paper aims to investigate the particle dynamic behavior in a rotating drum operating in a rolling regime under different rotating velocity, based on experimental results and simulations. Simple superphosphate fertilizer (SSP) was used as particulate matter in the current study. The Eulerian–Eulerian multiphase model along with the kinetic theory of granular flow was used in the simulations. In order to evaluate the simulation results, velocity distributions of the particulate phase were compared with experimental data. The experimental particle velocity distribution was obtained by using a high speed video camera. The numerical simulation results showed significant insights towards understanding of the particle dynamic in a rotating drum. The simulated results of particle velocity were in good agreement with the experimental data.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

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