Calculation of the Hydroplaning of a Deformable Smooth-Shaped and Longitudinally-Grooved Tire

1997 ◽  
Vol 25 (4) ◽  
pp. 265-287 ◽  
Author(s):  
H. Grogger ◽  
M. Weiss
Keyword(s):  
Pressure Distribution ◽  
Contact Area ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Water Film ◽  
Iterative Solution ◽  
Groove Depth ◽  
Surface Model ◽  
Finite Element Program ◽  
Lift And Drag

Abstract The dynamic hydroplaning of a deformable automobile tire is calculated. The three-dimensional flow around the tire is described by an efficient free surface model and the Navier-Stokes equations. The effects of turbulence are modeled by the well-known k,ε-model. The deformation of the tire is calculated using a noncommercial finite element program, in which all components of the three-dimensional tire are taken into account with their own mechanical and constitutive behavior. The deformation of the tire during stationary hydroplaning is found by an iterative solution procedure. The result of the calculation is the pressure distribution and the velocity field. The integration of the pressure distribution acting on the tire surface yields the lift and drag forces as well as lift and drag coefficients. The calculations are performed for a smooth-shaped tire at speeds of 30, 60, and 90 km/h driving speed and an 8 mm high water film. The results are compared with those of the undeformable tire. The calculated pressure distribution on the pavement shows very good agreement with experimentally obtained data. At 90 km/h the model predicts that the water penetrates the contact area of the tire whereas the tire still has contact with the road in the shoulder area. This is also found in experiments. Further, calculations are performed for a deformable tire with three circumferential grooves. Here the influence of different water depths at a speed of 90 km/h is investigated. The groove depth of the tire is 8 mm whereas the water depth varies between 4, 8, and 12 mm. The calculations show the intrusion of a water wedge into the contact area. As in previous studies it is found that the tire deformation has a very strong influence on the resulting lift forces.

Three-Dimensional Numerical Prediction of the Hydrodynamic Loads and Motions of Offshore Structures

2000 ◽  
Vol 122 (4) ◽  
pp. 294-300 ◽  
Author(s):  
Karl W. Schulz ◽  
Yannis Kallinderis
Keyword(s):  
Flow Structure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Structural Response ◽  
Offshore Structures ◽  
Three Dimensions ◽  
Navier Stokes ◽  
Hydrodynamic Loads ◽  
Drag Coefficients ◽  
Lift And Drag

A generalized numerical method for solution of the incompressible Navier-Stokes equations in three-dimensions has been developed. This solution methodology allows for the accurate prediction of the hydrodynamic loads on offshore structures, which is then combined with a rigid body structural response to address the flow-structure coupling which is often present in offshore applications. Validation results using this method are first presented for fixed structures which compare the drag coefficients of sphere and cylinder geometries to experimental measurements over a range of subcritical Reynolds numbers. Additional fixed structure results are then presented which explore the influence of aspect ratio effects on the lift and drag coefficients of a bare circular cylinder. Finally, the spanwise flow variations between a fixed and freely vibrating cylindrical structure are compared to demonstrate the ability of the flow-structure method to correctly predict correlation length increases for a vibrating structure. [S0892-7219(00)00904-3]

Three-dimensional dynamic hip contact area and pressure distribution during activities of daily living

2006 ◽  
Vol 39 (11) ◽  
pp. 1996-2004 ◽  
Author(s):  
H. Yoshida ◽  
A. Faust ◽  
J. Wilckens ◽  
M. Kitagawa ◽  
J. Fetto ◽  
...  
Keyword(s):  
Activities Of Daily Living ◽  
Pressure Distribution ◽  
Contact Area ◽  
Daily Living ◽  
Three Dimensional

Energy Conservation Law for the Turbulent Motion in the Free Atmosphere

2016 ◽  
pp. 105-138
Author(s):  
Kulyash Kaliyeva
Keyword(s):  
Pressure Distribution ◽  
Velocity Vector ◽  
Stokes Equations ◽  
Fundamental Problem ◽  
Three Dimensional ◽  
Successive Approximation Method ◽  
Free Atmosphere ◽  
Navier Stokes Equations ◽  
Divergent Flow ◽  
The Matrix

This chapter presents convergent-divergent flow in the free atmosphere which is governed by the three dimensional Navier-Stokes equations and deals with the fundamental problem of fluid dynamics. Considering air movement under influence divergence and rotation were found the true dependencies between the velocity vector and the pressure distribution. Following the classical procedure by using rotor operator and a well-known formula of vector analysis were obtained the second kind nonlinear Volterra-Fredholm integral equations in a matrix form which contained only three components of the velocity vector. According to the theory of the matrix operators were defined the velocity components by the successive approximation method. According to the obtained balance equation for the pressure distribution were defined significant properties of the transient convergent-divergent flow which provide a description of the constitutive relationships between three physical quantities: the velocity vector, the external and internal forces, the pressure distribution.

Calculation of the Three-Dimensional Free Surface Flow Around an Automobile Tire

1996 ◽  
Vol 24 (1) ◽  
pp. 39-49 ◽  
Author(s):  
H. Grogger ◽  
M. Weiss
Keyword(s):  
Free Surface ◽  
Pressure Distribution ◽  
Three Dimensional ◽  
Free Surface Flow ◽  
Equation System ◽  
Surface Flow ◽  
Automobile Tire ◽  
Drag Forces ◽  
On The Road ◽  
Lift And Drag

Abstract The 3D flow around a 195/65R15 automobile tire is calculated. To describe the free surface behavior with the usual conservation equations for mass and momentum, an additional equation for the water mass fraction is solved. For modeling the effects of turbulence, the well-known k,ε-model is used. The resulting fluid mechanics equation system is solved by a finite volume method. A finite element calculation considering inflation pressure and tire deflection gives the surface for the flow calculation. The goal is to determine the lift force of the tire at a certain velocity to predict the tendency of the tire to hydroplane. For a slick tire, the calculated pressure distribution in the water is presented. The lift and drag forces are evaluated from the pressure acting directly on the tire surface. The calculation is performed at three different velocities, 30, 60, and 90 km/h. A comparison with experimental data shows good agreement regarding the pressure distribution on the road in front of the tire.

scholarly journals Three-Dimensional Hydro-Magnetic Flow Arising in a Long Porous Slider and a Circular Porous Slider with Velocity Slip

Mathematics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 748 ◽  
Author(s):  
Naeem Faraz ◽  
Yasir Khan ◽  
Amna Anjum ◽  
Muhammad Kahshan
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Frictional Resistance ◽  
Mhd Flow ◽  
Velocity Slip ◽  
Convergent Series ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Homotopy Analysis ◽  
Lift And Drag

The current research explores the injection of a viscous fluid through a moving flat plate with a transverse uniform magneto-hydrodynamic (MHD) flow field to reduce sliding drag. Two cases of velocity slip between the slider and the ground are studied: a long slider and a circular slider. Solving the porous slider problem is applicable to fluid-cushioned porous sliders, which are useful in reducing the frictional resistance of moving bodies. By using a similarity transformation, three dimensional Navier–Stokes equations are converted into coupled nonlinear ordinary differential equations. The resulting nonlinear boundary value problem was solved analytically using the homotopy analysis method (HAM). The HAM provided a fast convergent series solution, showing that this method is efficient, accurate, and has many advantages over the other existing methods. Solutions were obtained for the different values of Reynolds numbers (R), velocity slip, and magnetic fields. It was found that surface slip and Reynolds number had substantial influence on the lift and drag of the long and the circular sliders. Moreover, the effects of the applied magnetic field on the velocity components, load-carrying capacity, and friction force are discussed in detail with the aid of graphs and tables.

A New Micro-Hydrodynamic Herringbone Bearing Using Slant Groove Depth Arrangements for Performance Enhancement

2017 ◽  
Vol 33 (5) ◽  
pp. 725-737
Author(s):  
Y. T. Lee ◽  
A. S. Yang ◽  
Y. H. Juan ◽  
C. S. Liu ◽  
Y. H. Chang
Keyword(s):  
Pressure Distribution ◽  
Performance Enhancement ◽  
Load Capacity ◽  
Three Dimensional ◽  
Measurement Data ◽  
Groove Depth ◽  
Friction Torque ◽  
Lubricant Film ◽  
Radial Stiffness ◽  
Good Agreement

AbstractThis study presents a new groove profile using the slant groove depth arrangements to enhance the performance of micro-HGJBs. The computational analysis was based on the steady-state three-dimensional conservation equations of mass and momentum in conjunction with the cavitation model to examine the complex lubricated flow field. The simulated results of load capacity and circumferential pressure distribution of lubricant film are in good agreement with the measurement data and the predictions cited in the literature. Numerical experiments were extended to determine the pressure distribution, load capacity, radial stiffness and friction torque by varying the slant ratio of groove depth, eccentricity ratio, rotational speed and attitude angle. The cavitation extent of lubricant film was also studied for different slant groove patterns.

Method for Calculating Plastic Deformation of High Resolution and Large Contact Area

2021 ◽  
Vol 144 (1) ◽  
Author(s):  
S. Sklenak ◽  
D. Mevissen ◽  
J. Brimmers ◽  
C. Brecher
Keyword(s):  
Plastic Deformation ◽  
High Resolution ◽  
Pressure Distribution ◽  
Rough Surface ◽  
Tribological Properties ◽  
Contact Area ◽  
Three Dimensional ◽  
Rolling Contact ◽  
Contact Algorithm ◽  
Large Contact Area

Abstract In a rolling contact, the tribological properties in terms of friction, wear, and fatigue are significantly influenced by the surface roughness. Due to solid contact of the surfaces in the contact area, the roughness and thus also the tribological properties change during the service life of the contact. The initial load leads to major changes of the tribological properties figured out by Brecher et al. (2019, “Influence of the Metalworking Fluid on the Micropitting Wear of Gears,” Wear, 61(434–435), p. 202996). Prediction of the initial changes in topography in the contact area is necessary for specific optimization of rolling contacts. Especially for dry rolling–sliding contact, the roughness of the surfaces is crucial for the lifetime, which is part of the investigations within the DFG priority program 2074 (357505886). In this work, an elastic-plastic contact algorithm for calculating plastic deformation for dry contact of rough surfaces with large contact area and high resolution is presented. Due to the nonlinearity behavior associated with plastic deformation, the plastic contact algorithm is based on an iterative approach. An optimized meshing strategy is implemented to calculate the elastic pressure distribution on the surface. Corresponding to the two-dimensional pressure distribution, the three-dimensional stress distribution allows the consideration of residual stresses and interactions of the microscopic peaks of the rough surface. Furthermore, the three-dimensional plastic strain distribution allows the application of an analytical approach to represent the plastic deformation of the surface. Finally, the solution of a plastic contact calculation with an exemplary topography measured on a real rough surface is presented.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Measurement and Visualization of the Contact Pressure Distribution of Rubber Disks and Tires

1995 ◽  
Vol 23 (4) ◽  
pp. 238-255 ◽  
Author(s):  
E. H. Sakai
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Area ◽  
Light Absorption ◽  
Lateral Force ◽  
Contact Pressure Distribution ◽  
High Definition ◽  
The Road ◽  
Close Relationship ◽  
Processing Techniques

Abstract The contact conditions of a tire with the road surface have a close relationship to various properties of the tire and are among the most important characteristics in evaluating the performance of the tire. In this research, a new measurement device was developed that allows the contact stress distribution to be quantified and visualized. The measuring principle of this device is that the light absorption at the interface between an optical prism and an evenly ground or worn rubber surface is a function of contact pressure. The light absorption can be measured at a number of points on the surface to obtain the pressure distribution. Using this device, the contact pressure distribution of a rubber disk loaded against a plate was measured. It was found that the pressure distribution was not flat but varied greatly depending upon the height and diameter of the rubber disk. The variation can be explained by a “spring” effect, a “liquid” effect, and an “edge” effect of the rubber disk. Next, the measurement and image processing techniques were applied to a loaded tire. A very high definition image was obtained that displayed the true contact area, the shape of the area, and the pressure distribution from which irregular wear was easily detected. Finally, the deformation of the contact area and changes in the pressure distribution in the tread rubber block were measured when a lateral force was applied to the loaded tire.

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