Tire Splash and Spray Directly before and during Hydroplaning

2019 ◽  
Vol 47 (2) ◽  
pp. 141-159 ◽  
Author(s):  
Bernhard Schmiedel ◽  
Frank Gauterin
Keyword(s):  
Image Processing ◽  
Film Thickness ◽  
High Speed ◽  
Test Bench ◽  
Water Film ◽  
Water Film Thickness ◽  
Additional Information ◽  
Almost All ◽  
Main Effects ◽  
Require Information

ABSTRACT Wet roads can have a serious impact on tire traction. There are several ways of detecting wet roads; however, almost all of them come with disadvantages. Using the splash and spray behavior of the tire can offer a solution. To identify key parameters that influence splash and spray, we used high-speed cameras to record tires rolling on an internal drum tire test bench. The key parameters were water film thickness, speed, and profile geometry (tread pattern and tread depth). Our image-processing analysis showed three main effects in the splash and spray behavior that help to characterize the water film thickness: side splash, circumferential spray, and torrent spray. Circumferential spray and torrent spray can be used to estimate low and medium water film thicknesses, but these require information about speed and profile geometry. Side splash announces hydroplaning without the need for additional information.

Numerical analysis for the influence of water film on adhesion between rail and wheel

1998 ◽  
Vol 212 (5) ◽  
pp. 359-368 ◽  
Author(s):  
H Chen ◽  
A Yoshimura ◽  
T Ohyama
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Material Parameter ◽  
Numerical Solutions ◽  
Adhesion Force ◽  
Elastohydrodynamic Lubrication ◽  
Water Film ◽  
Rolling Speed ◽  
Linear Regression Method ◽  
Water Film Thickness

The adhesion force between rail and wheel is one of the important factors for proceeding towards the realization of high-speed railway. On the other hand, it is supposed that the water film formed between the rail and wheel has a remarkable influence on the adhesion force under rainy condition at higher speeds. In this paper, taking Bett and Cappi's viscosity values of water, which show quite a different behaviour from the viscosity of oil, the influence has been investigated of important factors such as rolling speed, contact pressure and temperature on water film thickness for a smooth surface by applying elastohydrodynamic lubrication theory. Based on the numerical solutions, an empirical equation has been developed for water film thickness relating to rolling speed, load and material parameter by using a linear regression method and comparing it with other authors' works on a lower material parameter or elastic-isoviscous contact. Furthermore, in order to understand the influence of the above factors and the surface roughness on the adhesion force, adhesion coefficients have been calculated on a trial basis in the case of rough surface contact under limited conditions, and the theoretical results have been compared with the measured values of the tests on Japanese Shinkansen vehicles in the field.

Influence of Ground Slag on the Rheology of Mortar

2013 ◽  
Vol 438-439 ◽  
pp. 67-71
Author(s):  
Qian Qian Zhang ◽  
Jian Zhong Liu ◽  
Jia Ping Liu
Keyword(s):  
Film Thickness ◽  
Specific Surface ◽  
Yield Stress ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Film ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Water Film Thickness ◽  
Binder Ratio

The effects of ground slag with different specific surface area on the rheology of mortar at water-binder ratio of 0.25, 0.28 and 0.30 were investigated, and the combined effects of packing density and solid surface area on the rheology of mortar were evaluated in terms of the water film thickness. The results show that with the increasing of specific surface area of slag (220 m2/kg-784 m2/kg), plastic viscosity and yield stress decrease. The correlations of yield stress and plastic viscosity to the water film thickness are basically linear with high correlation R2 values. The action of the ground slag on the rheology of mortar can be characterized by water film thickness, and with the increasing of water film thickness the rheological parameters decrease.

Measuring Water Film Thickness in a Wet Gas Compressor Diffuser: Design, Calibration, and Testing of Electromagnetic Probes

2017 ◽  
Author(s):  
Craig Nolen ◽  
Melissa Poerner
Keyword(s):  
Film Thickness ◽  
Water Level ◽  
Water Film ◽  
Probe Design ◽  
Two Phase ◽  
Water Film Thickness ◽  
Wet Gas ◽  
Flow Phenomena ◽  
In Series ◽  
Electromagnetic Probes

The distribution of water in the diffuser of a wet gas compressor is not well understood. Measurements of water film thickness across the diffuser surface would improve the understanding of two-phase flow phenomena in wet gas compressors. Electromagnetic probes were designed in order to measure water film thickness in the diffuser of a SwRI-designed wet gas compressor. The probes consisted of two electrode foils plated on a thin insulating substrate, allowing them to be bonded in place without drilling through the diffuser. An AC signal was passed between the electrodes, and the voltage across a resistor in series with the electrodes was recorded. As the water level covering the electrodes increased, the recorded voltage increased. A method of calibrating the probes was developed and used prior to installation in the diffuser. Testing showed the probes to be effective at detecting the presence of water in the diffuser and indicating the general water level. Improvements in probe design, calibration, and installation are needed to provide more precise water film thickness data.

Effects and threshold of water film thickness on multi-mineral cement paste

2020 ◽  
Vol 112 ◽  
pp. 103677 ◽  
Author(s):  
Hengrui Liu ◽  
Xiao Sun ◽  
Hui Du ◽  
Hao Lu ◽  
Yuanshan Ma ◽  
...  
Keyword(s):  
Film Thickness ◽  
Cement Paste ◽  
Water Film ◽  
Water Film Thickness
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