scholarly journals Internal Pressure Waves and Troposphere Dynamics

1966 ◽  
Vol 39 (6) ◽  
pp. 1261-1261
Author(s):  
Jessie M. Young ◽  
Howard S. Bowman
Keyword(s):  
Internal Pressure ◽  
Pressure Waves

scholarly journals Impulsive Motion in a Cylindrical Fluid-Filled Tube Terminated by a Converging Section

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Jean-Christophe Veilleux ◽  
Joseph E. Shepherd
Keyword(s):  
Free Surface ◽  
Internal Pressure ◽  
Model System ◽  
Complex Interaction ◽  
Normal Operation ◽  
Pressure Waves ◽  
Metal Tube ◽  
Impulsive Motion ◽  
Injection Mechanism ◽  
Auto Injector

The syringe in a subcutaneous auto-injector may be subjected to internal pressure transients due to the normal operation of the injection mechanism. These transients are similar to transients in fluid-filled pipelines observed during water hammer events. In this paper, the effect of an air gap in the syringe and a converging section is studied experimentally and numerically in a model system which consists of a fluid-filled metal tube that is impulsively loaded with a projectile to simulate the action of the auto-injector mechanism operation. The air between the buffer and the water results in a complex interaction between the projectile and the buffer. Also, there are tension waves inside the tube due to the presence of a free surface and the motion of the buffer, and this causes distributed cavitation which, in turn, gives rise to steepening of the pressure waves. The converging section can amplify the pressure waves if the wave front is sharp, and it can enhance the collapse of bubbles. Pressures as high as 50 MPa have been measured at the apex of the cone with impact velocities of 5.5 m/s.

Impulsively-Generated Pressure Transients and Strains in a Cylindrical Fluid-Filled Tube Terminated by a Converging Section

2017 ◽  
Author(s):  
Jean-Christophe Veilleux ◽  
Joseph E. Shepherd
Keyword(s):  
Free Surface ◽  
Internal Pressure ◽  
Wave Front ◽  
Model System ◽  
Complex Interaction ◽  
Normal Operation ◽  
Pressure Waves ◽  
Metal Tube ◽  
Pressure Transients ◽  
Injection Mechanism

The syringe in a subcutaneous autoinjector may be subjected to internal pressure transients due to the normal operation of the injection mechanism. These transients are similar to transients in fluid-filled pipelines observed during water hammer events. In this paper, the effect of an air gap in the syringe and a converging section are studied experimentally and numerically in a model system which consists of a fluid-filled metal tube that is impulsively loaded with a projectile to simulate the action of the autoinjector mechanism operation. The air between the buffer and the water results in a complex interaction between the projectile and the buffer. Also, there are tension waves inside the tube due to the presence of a free surface, and this causes distributed cavitation which, in turn, gives rise to steepening of the pressure waves. The converging section can amplify the pressure waves if the wave front is sharp. Pressures as high as 50 MPa have been measured at the apex of the cone with impact velocities of 5.5 m/s.

Semi-empirical model of internal pressure for a high-speed train under the excitation of tunnel pressure waves

2021 ◽  
pp. 095440972110427
Author(s):  
Chun-jun Chen ◽  
Zhi-ying He ◽  
Yong-ping Feng ◽  
Lu Yang
Keyword(s):  
Internal Pressure ◽  
High Speed ◽  
Coupling Model ◽  
Air Pressure ◽  
Dominant Factor ◽  
Pressure Waves ◽  
Factors Affecting ◽  
High Speed Trains ◽  
Method Effects ◽  
Semi Empirical

To study the transmission of air pressure from external to internal carriage of high-speed trains, an internal pressure model excited by tunnel pressure wave is established. Firstly, factors affecting the air pressure transmission are analysed. Then, the semi-empirical models of the internal pressure caused by a single factor are established based on both the theoretical analysis and experimental data: (1) by applying the finite element method, effects of carbody deformation are studied; (2) based on the static air tightness test, the transmission from the gaps is modelled and (3) the model of the air ducts are surveyed on the base of the characteristics of the ventilation fans and valves. Finally, three routes are comprehensively considered and a coupling model of the internal pressure is established. Simulation results shows the model is adaptable in predicting the internal pressure under excitation of tunnel pressure waves. Besides, the effect of the factors on internal pressure are studied based on the models. Among the factors, the deformation has the least effect. Meanwhile, the air ducts are the dominant factor that affects the internal pressure at high opening degree, while the gaps will become the dominant factor when the opening degree of air ducts is relatively low.

Dependence of Internal Pressure-rise due to Arc on Current Waveform and Ignition Position

2011 ◽  
Vol 131 (7) ◽  
pp. 574-583 ◽  
Author(s):  
Shin-ichi Tanaka ◽  
Tsukasa Miyagi ◽  
Mikimasa Iwata ◽  
Tadashi Amakawa
Keyword(s):  
Internal Pressure ◽  
Pressure Rise ◽  
Current Waveform

Validation of a Belt Model for Prediction of Hub Forces from a Rolling Tire4

2009 ◽  
Vol 37 (2) ◽  
pp. 62-102 ◽  
Author(s):  
C. Lecomte ◽  
W. R. Graham ◽  
D. J. O’Boy
Keyword(s):  
Internal Pressure ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Prediction Method ◽  
Analytical Models ◽  
Beam Model ◽  
Impedance Boundary ◽  
Bending Waves ◽  
Tire Rotation ◽  
Three Dimensional Models

Abstract An integrated model is under development which will be able to predict the interior noise due to the vibrations of a rolling tire structurally transmitted to the hub of a vehicle. Here, the tire belt model used as part of this prediction method is first briefly presented and discussed, and it is then compared to other models available in the literature. This component will be linked to the tread blocks through normal and tangential forces and to the sidewalls through impedance boundary conditions. The tire belt is modeled as an orthotropic cylindrical ring of negligible thickness with rotational effects, internal pressure, and prestresses included. The associated equations of motion are derived by a variational approach and are investigated for both unforced and forced motions. The model supports extensional and bending waves, which are believed to be the important features to correctly predict the hub forces in the midfrequency (50–500 Hz) range of interest. The predicted waves and forced responses of a benchmark structure are compared to the predictions of several alternative analytical models: two three dimensional models that can support multiple isotropic layers, one of these models include curvature and the other one is flat; a one-dimensional beam model which does not consider axial variations; and several shell models. Finally, the effects of internal pressure, prestress, curvature, and tire rotation on free waves are discussed.

Stress Analysis of Tire Sections

1996 ◽  
Vol 24 (4) ◽  
pp. 349-366 ◽  
Author(s):  
T-M. Wang ◽  
I. M. Daniel ◽  
K. Huang
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Strain Analysis ◽  
Experimental Stress ◽  
Inflation Pressure ◽  
Substantial Agreement ◽  
Finite Element Stress Analysis ◽  
Strain Components ◽  
Fringe Patterns

Abstract An experimental stress-strain analysis by means of the Moiré method was conducted in the area of the tread and belt regions of tire sections. A special loading fixture was designed to support the tire section and load it in a manner simulating service loading and allowing for Moiré measurements. The specimen was loaded by imposing a uniform fixed deflection on the tread surface and increasing the internal pressure in steps. Moiré fringe patterns were recorded and analyzed to obtain strain components at various locations of interest. Maximum strains in the range of 1–7% were determined for an effective inflation pressure of 690 kPa (100 psi). These results were in substantial agreement with results obtained by a finite element stress analysis.

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