The Normal Approach, Contact, and Rebound of Lubricated Cylinders

1983 ◽  
Vol 105 (2) ◽  
pp. 271-279 ◽  
Author(s):  
A. Chandra ◽  
R. J. Rogers
Keyword(s):  
Experimental Data ◽  
Pressure Distribution ◽  
Constant Load ◽  
Contact Forces ◽  
Solid Model ◽  
Two Dimensional ◽  
Load Case ◽  
Inertia Effects ◽  
Pressure Distributions ◽  
Present Technique

An algorithm has been developed to simulate the normal approach, contact, and rebound of lubricated cylinders. The detailed interaction between the lubricated cylinders is predicted, thus providing the pressure distribution, contact forces, and other variables useful in predicting rates of wear. The present technique improves on the existing elastohydrodynamic (EHD) models in the following areas: (1) during contact a solid-solid model is used; (2) a two-dimensional analysis is used to obtain the pressure distributions in both the circumferential and axial directions; (3) inertia effects are approximated; and (4) any specified load can be treated. The simulated results for the constant load case are compared with the results of Wada and Tsukijihara and a formula developed by Cameron. For sinusoidal loads the results are compared with experimental data from a cylinder and sleeve apparatus.

Generalization of Experimental Data for Compressor Cascades at Low Speeds

1970 ◽  
Author(s):  
V. S. Beknev
Keyword(s):  
Experimental Data ◽  
Pressure Distribution ◽  
Loss Coefficient ◽  
Two Dimensional ◽  
Minimum Loss ◽  
Maximum Value ◽  
Isentropic Exponent ◽  
Loss Coefficients ◽  
Low Speeds ◽  
Drag Ratio

The author compares three different approaches for generalization of experimental data for two-dimensional compressor cascades at low speeds: generalization for maximum value of lift-drag ratio, generalization for maximum cascade quality, and generalization for minimum loss coefficient. Some results given, of comparison for incidence and deviation angles, solidities, and loss coefficients, show the largest difference to be for incidence angles and loss coefficients. Influence of isentropic exponent on the airfoil pressure distribution and cascade losses is considered.

Pressure Distributions and Forces on Rectangular and D-shaped Cylinders

1972 ◽  
Vol 23 (1) ◽  
pp. 1-6 ◽  
Author(s):  
B R Bostock ◽  
W A Mair
Keyword(s):  
Boundary Layer ◽  
Circular Cylinder ◽  
Drag Coefficient ◽  
Pressure Distribution ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Two Dimensional Flow ◽  
Rectangular Cylinders ◽  
Shaped Section

SummaryMeasurements in two-dimensional flow on rectangular cylinders confirm earlier work of Nakaguchi et al in showing a maximum drag coefficient when the height h of the section (normal to the stream) is about 1.5 times the width d. Reattachment on the sides of the cylinder occurs only for h/d < 0.35.For cylinders of D-shaped section (Fig 1) the pressure distribution on the curved surface and the drag are considerably affected by the state of the boundary layer at separation, as for a circular cylinder. The lift is positive when the separation is turbulent and negative when it is laminar. It is found that simple empirical expressions for base pressure or drag, based on known values for the constituent half-bodies, are in general not satisfactory.

A Numerical Treatment for Attached Cavitation

1994 ◽  
Vol 116 (3) ◽  
pp. 613-618 ◽  
Author(s):  
Yongliang Chen ◽  
Stephen D. Heister
Keyword(s):  
Experimental Data ◽  
Wall Pressure ◽  
Two Dimensional ◽  
Numerical Treatment ◽  
Cavitation Model ◽  
Pressure Distributions ◽  
Cavitation Region ◽  
Bubble Length ◽  
Body Shapes ◽  
Two Dimensional Flows

A new numerical treatment has been developed for the prediction of the flowfield resulting from an attached cavitation region. The cavitation model has been implemented in a viscous calculation which is an improvement over previous inviscid results. The model requires no apriori knowledge of the wall detachment point or bubble length and comparisons with experimental data indicate good predictions of these quantities for a variety of different body shapes and cavitation numbers. Furthermore, wall pressure distributions are also predicted quite accurately using this method. While the treatment has been applied to an axisymmetric calculation, the approach should be applicable to two-dimensional flows.

Two-Dimensional Contact Pressure Distribution of a Radial Tire

1990 ◽  
Vol 18 (2) ◽  
pp. 80-103 ◽  
Author(s):  
T. Akasaka ◽  
M. Katoh ◽  
S. Nihei ◽  
M. Hiraiwa
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Side Wall ◽  
Bending Moment ◽  
Two Dimensional ◽  
Contact Pressure Distribution ◽  
Friction Forces ◽  
Radial Tire ◽  
Pressure Distributions ◽  
Reaction Forces

Abstract Two-dimensional contact pressure distribution of a radial tire, statically compressed to a flat roadway, is analyzed using a rectangular contact patch. The tire structure is modeled by a spring-bedded ring belt comprised of a laminated-biased composite strip. The belt is supported by radial springs simulating the sidewall. The spring constant Kr was well defined previously by one of the authors. Deformation of the rectangular flat belt is obtained theoretically. The belt is subjected to inflation pressure, reaction forces transmitted from the spring bed of the tread rubber, and shearing force and bending moment along the belt boundaries brought from side-wall springs and the detached part of the ring belt. In-plane membrane forces, which are not uniform in the contact area, due to the friction forces acting between the tread surface and the roadway are also applied. The resulting contact pressure distributions in the circumferential direction are shown to be convex along the shoulder, but concave along the crown center line. This distribution agrees well with the experimental results.

Instability and Transition in a Separation Bubble Under a Three-Dimensional Freestream Pressure Distribution

2011 ◽  
Vol 134 (3) ◽  
Author(s):  
M. I. Yaras
Keyword(s):  
Boundary Layer ◽  
Pressure Distribution ◽  
Pressure Field ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Test Surface ◽  
Two Dimensional ◽  
Transition Processes ◽  
Pressure Distributions ◽  
Separation Bubbles

This paper presents measurements of the instability and transition processes in separation bubbles under a three-dimensional freestream pressure distribution. The measurements are performed on a flat plate on which a pressure distribution is imposed by a contoured surface facing the flat test-surface. The three-dimensional pressure distribution that is established on the test-surface approximates the pressure distributions encountered on swept blades. This type of pressure field produces crossflows in the laminar boundary layer upstream of the separation and within the separation bubble. The effects of these crossflows on the instability of the upstream boundary layer and on the instability, transition onset, and transition rate within the separated shear-layer are examined. The measurements are performed at two flow-Reynolds numbers and relatively low level of freestream turbulence. The results of this experimental study show that the three-dimensional freestream pressure field and the corresponding redistribution of the freestream flow can cause significant spanwise variation in the separation-bubble structure. It is demonstrated that the instability and transition processes in the modified separation bubble develop on the basis of the same fundamentals as in two-dimensional separation bubbles and can be predicted with the same level of accuracy using models that have been developed for two-dimensional separation bubbles.

Instability and Transition in a Separation Bubble Under a Three-Dimensional Freestream Pressure Distribution

2008 ◽  
Author(s):  
M. I. Yaras
Keyword(s):  
Boundary Layer ◽  
Pressure Distribution ◽  
Pressure Field ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Test Surface ◽  
Two Dimensional ◽  
Transition Processes ◽  
Pressure Distributions ◽  
Separation Bubbles

This paper presents measurements of the instability and transition processes in separation bubbles under a three-dimensional freestream pressure distribution. Measurements are performed on a flat plate upon which a pressure distribution is imposed by a contoured surface facing the flat test surface. The three-dimensional pressure distribution that is established on the test surface approximates the pressure distributions encountered on swept blades. This type of pressure field produces crossflows in the laminar boundary layer upstream of separation and within the separation bubble. The effects of these crossflows on the instability of the upstream boundary layer and on the instability, transition onset and transition rate within the separated shear layer are examined. The measurements are performed at two flow Reynolds numbers and relatively low level of freestream turbulence. The results of this experimental study show that the three-dimensional freestream pressure field and the corresponding redistribution of the freestream flow cause significant spanwise variation of the separation-bubble structure. It is demonstrated that the instability and transition processes in the modified separation bubble develop on the basis of the same fundamentals as in two-dimensional separation bubbles, and can be predicted with the same level of accuracy using models that have been developed for two-dimensional separation bubbles.

Evaluation of Pressure Distribution on a Cavitating Hydrofoil With Flap

1967 ◽  
Vol 11 (02) ◽  
pp. 93-108
Author(s):  
Z. L. Harrison ◽  
Duen-pao Wang
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Pressure Distribution ◽  
Flat Plate ◽  
Flow Model ◽  
Wake Flow ◽  
Two Dimensional ◽  
The Moment ◽  
Cavitating Hydrofoil ◽  
General Method

A general method is established to calculate the pressure distribution and the moment of force for a two-dimensional, supercavitating hydrofoil with a flap. The wake flow model is adopted to describe the configuration of the flow field. Some numerical results for a supercavitating flat plate with a flap are compared with the corresponding experimental data.

Finite Cavity Cascades With Low-Drag Pressure Distributions

1973 ◽  
Vol 95 (1) ◽  
pp. 8-16
Author(s):  
B. Yim
Keyword(s):  
Pressure Distribution ◽  
Finite Length ◽  
Nonlinear Approximation ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Two Dimensional ◽  
Method Of Calculation ◽  
Pressure Distributions

A method of calculation is presented for the flow characteristics of a two-dimensional supercavitating cascade with finite-length cavities and with an arbitrary pressure distribution. The principle of hydrofoil-airfoil correspondence of the infinite-cavity cascade is utilized. Simplified formulas for the drag and the cavity and foil shapes are derived, and several sample calculations are made. A nonlinear approximation for a thick leading-edge shape is also considered.

Expressions for the Viscosity of Liquid/Vapour Mixtures: Predicted and Measured Pressure Distributions in a Hydrostatic Bearing

1996 ◽  
Vol 210 (1) ◽  
pp. 75-79 ◽  
Author(s):  
N Saadat ◽  
W L Flint
Keyword(s):  
Experimental Data ◽  
Pressure Distribution ◽  
Thrust Bearing ◽  
Two Phase ◽  
Hydrostatic Bearing ◽  
Pressure Distributions ◽  
Phase Mixture ◽  
Predicted Values ◽  
The Individual ◽  
Measured Pressure

The present paper reports the correlation between the predicted performance and experimental data obtained from a hydrostatic thrust bearing under conditions designed to produce phase change due to viscous dissipation within the lubricant. The predicted values of pressure distribution indicate that the best correlation is obtained when the viscosity of a two-phase mixture is assumed to be the volume average of the viscosity of the individual phases.

Investigations Concerning Flow Patterns Within the Impeller Channels of Radial-Inflow Turbines, With Some Reference to the Influence of the Splitter Vanes

1967 ◽  
Vol 89 (4) ◽  
pp. 463-476 ◽  
Author(s):  
Ichiro Ariga ◽  
Ichiro Watanabe ◽  
Kunio Fujie
Keyword(s):  
Experimental Data ◽  
Relative Velocity ◽  
Static Pressure ◽  
Rotation Speed ◽  
Flow Patterns ◽  
Two Dimensional ◽  
Performance Parameters ◽  
Pressure Distributions ◽  
Theoretical Predictions ◽  
Theoretical Results

The experimental results of the relative velocity distributions together with the static pressure distributions within the impeller channels of radial-inflow turbines with and without splitter vanes are presented. The flow patterns within three stream surfaces (blade-to-blade surfaces) having different passage depths are shown using two performance parameters, i.e., nondimensional weight flow and nondimensional rotation speed. The impellers used were of purely radial type or of two-dimensional type. Further, theoretical predictions for the relative velocity distributions within the impeller channels having no splitter vanes were conducted, and comparisons of the theoretical results with experimental data were made.

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