Characterization of the Pressure Wave Emitted From Implosion of Submerged Cylindrical Shell Structures

2012 ◽  
Author(s):  
Michael D. Shields ◽  
Pawel Woelke ◽  
Najib N. Abboud
Keyword(s):  
Pressure Wave ◽  
Pressure Pulse ◽  
Peak Pressure ◽  
Structural Parameters ◽  
Shell Structures ◽  
High Fidelity ◽  
Pressure Waves ◽  
Structural Configurations ◽  
The Impact

Buckling of submerged cylindrical shells is a sudden and rapid implosion which emits a high pressure pulse that may be damaging to nearby structures. The characteristics of this pressure pulse are dictated by various parameters defining the shell structure such as the length to diameter ratio, shell thickness, material, and the existence and configuration of internal stiffeners. This study examines, through the use of high fidelity coupled fluid-structure finite element computations, the impact of various structural parameters on the resulting pressure wave emanating from the implosion. The results demonstrate that certain structural configurations produce pressure waves with higher peak pressure and impulse thereby enhancing the potential for damage to nearby structures.

Active Air Control System Development Using Charge Air Integrated Manifold Engine Numerical Simulation (CAIMENS)

2007 ◽  
Author(s):  
Diana K. Grauer ◽  
Kirby S. Chapman ◽  
Ali Keshavar
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Wave ◽  
Equivalence Ratio ◽  
Peak Pressure ◽  
Intake Manifold ◽  
Airflow Rate ◽  
Engine System ◽  
The Impact

The natural gas transmission industry integrates turbochargers into the engine system to strategically increase airflow for the purpose of decreasing pollutant emissions, such as Nitrogen Oxide (NOX). Regulations are expected to be tightened in the coming years, forcing transmission companies to look past turbochargers for compliance. The solution to further decreasing emissions lies not in further retrofit, but focusing on the physics of the current system. The flow rate physics of the intake and exhaust manifolds impede equal distribution of air from the turbocharger to each cylinder. Imbalance in airflow creates a discontinuity in the trapped equivalence ratio from cylinder to cylinder. The trapped equivalence ratio is directly proportional to NOX production and a function of the fuel flow rate, airflow rate, and, in two-stroke cycle engines, the scavenging efficiency. Only when these three characteristics are balanced cylinder to cylinder will the combustion and the NOX production in each cylinder be equal. The engine NOX production will be disproportionately high if even one cylinder operates less lean relative to the other cylinders. Balancing the NOX production between cylinders can lower the overall NOX production of the engine. This paper reports on an investigation into the transient, compressible flow physics that impact the trapped equivalence ratio. A comprehensive, variable geometry, multi-cylinder Turbocharger-Reciprocating Engine Computer Simulation (T-RECS) has been developed to illustrate the effect of airflow imbalance on an engine. A new model, the Charge Air Integrated Manifold Engine Numerical Simulation (CAIMENS), is a manifold flow model coupled with the T-RECS engine processor that uses an integrated set of fundamental principles to determine the crank angle-resolved pressure, temperature, burned and unburned mass fractions, and gas exchange rates for the cylinder. CAIMENS has the ability to show the transient impact of one cylinder firing on each successive cylinder. The pulsation model also describes the impact of manifold pressure drop on in-cylinder peak pressure and the pressure wave introduced to the intake manifold by uncovering the intake ports. CAIMENS provides the information necessary to quantify the impact of airflow imbalance, and allows for the visualization of the engine system before and after airflow correction. The model shows that not only does the manifold pressure drop have a significant impact on the in-cylinder peak pressure, but it also has an impact on the pressure wave introduced to the intake manifold as the ports are opened. Also, each cylinder has a considerable impact on the airflow into each successive cylinder.

Propagation velocity and reflection of pressure waves in the canine coronary artery

1979 ◽  
Vol 237 (4) ◽  
pp. H469-H474 ◽  
Author(s):  
T. Arts ◽  
R. T. Kruger ◽  
W. van Gerven ◽  
J. A. Lambregts ◽  
R. S. Reneman
Keyword(s):  
Coronary Artery ◽  
High Frequency ◽  
Pressure Wave ◽  
Pressure Pulse ◽  
Peripheral Resistance ◽  
Low Frequency ◽  
Pressure Waves ◽  
Cross Sectional ◽  
Frequency Components ◽  
Canine Coronary Artery

In this study the pressure wave velocity in the anterior descending branch of the left coronary artery (LADC) of the dog was measured by determining the delay time between pressure pulses along this artery. This method can only be applied if reflections of the pressure wave distal to the sites of pressure measurement are insignificant. From araldite casts of the coronary arteries the following relation between the diameter proximal to (dprox) and distal to (ddist 1, ddist 2) a bifurcation was found: dprox2.55 = ddist12.55 + ddist 22.55, indicating that reflections at a bifurcation areminimal. In dogs reflections were studied by inducing during diastole a pressure pulse in the aorta and measuring pressure and volume flow proximal to and pressure distal to a segment of the LADC at various levels of the coronary peripheral resistance. Reflection of high-frequency components (greater than 7 Hz) was found to be insignificant, allowing application of the above-mentioned method for measuring the wave-front velocity, which is insensitive to low-frequency reflection. At a pressure in the LADC of 13.3 kPa this velocity was 8.6 +/- 1.4 m.s-1 (mean +/- SD). The calculated dynamic cross-sectional stiffness (deltaP/(deltaA/A)) of the LADC was 97 +/- 11 kPa (mean +/- SE) at an arterial pressure of 13.3 kPa.

scholarly journals Sonic and Impact Test for Structural Assessment of Historical Masonry

2019 ◽  
Vol 9 (23) ◽  
pp. 5148 ◽  
Author(s):  
Alessandro Grazzini
Keyword(s):  
Impact Test ◽  
Structural Parameters ◽  
Historical Masonry ◽  
2016 Amatrice Earthquake ◽  
The Impact ◽  
Santa Maria ◽  
Non Destructive ◽  
Non Destructive Techniques

Diagnostics is a very important tool of knowledge in the field of historical buildings. In particular, non-destructive techniques allow to deepen the study of the mechanical characteristics of the historical walls without compromising the artistic value of the monumental building. A case study of the use of sonic and impact tests was described, performed using the same instrumented hammer, for the characterization of the masonry walls at the Sanctuary of Santa Maria delle Grazie at Varoni, one of the churches damaged in the 2016 Amatrice earthquake. Sonic tests showed the presence of a discontinous masonry texture, as well as confirming the ineffectiveness of the strengthening work made by injections of lime mortar. The impact test allowed us to obtain the elastic modulus of the omogeneous stones of the masonry. The results obtained from the non-destructive techniques were confirmed by the flat jacks test carried out on the building, confirming the great potential of the non-destructive diagnostics suitable for analyzing important structural parameters without affecting the preservation of historical masonry structures.

scholarly journals Pressure Wave Caused by Trinitrotoluene Underwater Explosion

2020 ◽  
Author(s):  
Radosław Kiciński
Keyword(s):  
Pressure Wave ◽  
Bubble Formation ◽  
Underwater Explosion ◽  
Computer Hardware ◽  
Acoustic Medium ◽  
Computational Techniques ◽  
Pressure Waves ◽  
Underwater Explosions ◽  
Explosion Pressure ◽  
The Impact

The development of computational techniques and computer hardware has an impact the analysis of short-term (fast-changing) processes, such as the impact of a non-contact underwater explosion pressure waves. A theory of underwater explosions, gas bubble formation and pressure waves are presented. The course of the pressure wave in time, and its propagation in the acoustic medium are presented. Entry presents empirical descriptions of non-contact pressure explosion waves. 

scholarly journals Elastic Properties Estimation of Masonry Walls through the Propagation of Elastic Waves. An Experimental Investigation

2021 ◽  
Vol 11 (19) ◽  
pp. 9091
Author(s):  
Jacopo Marazzani ◽  
Nicola Cavalagli ◽  
Vittorio Gusella
Keyword(s):  
Elastic Waves ◽  
Structural Parameters ◽  
Masonry Walls ◽  
Artistic Value ◽  
Masonry Material ◽  
Historical Masonry ◽  
The Impact ◽  
Propagation Of Elastic Waves ◽  
Non Destructive

Structural identification is one of the most important steps when dealing with historic buildings. Knowledge of the parameters, which define the mechanical properties of these kinds of structures, is fundamental in preparing interventions aimed at their restoration and strengthening, especially if they have suffered damage due to strong events. In particular, by using non-destructive techniques it is possible to estimate the mechanical characteristics of load-bearing structures without compromising the artistic value of the monumental buildings. In this paper, after recalling the main theoretical aspects, the use of elastic waves propagation through impact tests for the characterization of the masonry walls of a monumental building is described. The impact test allowed us to estimate the elastic characteristics of the homogeneous solid equivalent to masonry material. This confirms the great potential of the non-destructive diagnostics suitable for analyzing important structural parameters without affecting the preservation of historical masonry structures.

Transient Phenomena in Wave Propagation around a Large Suspended Particle in a Water-Filled Tube

2014 ◽  
Vol 566 ◽  
pp. 431-436
Author(s):  
Tatsuro Hori ◽  
Kazuaki Inaba ◽  
Kosuke Takahashi ◽  
Kikuo Kishimoto
Keyword(s):  
Pressure Wave ◽  
Suspended Particle ◽  
Free Fall ◽  
Stress Waves ◽  
Pressure Waves ◽  
Hoop Strain ◽  
Transient Phenomena ◽  
Elastic String ◽  
Particle Material ◽  
The Impact

Our study focuses on the response of a water-filled polycarbonate tube under axial impact loading to the presence of a single large suspended particle. The particles, composed of steel, aluminum, and polycarbonate, were individually suspended by elastic string along the centerline of the tube. The impact of a free-fall piston initiated pressure waves in the water, called water hammer, and stress waves in the tube, especially at the level of the particle. Hoop strains were measured as impact responses; their distribution indicated that the maximum strains occurred around the particle. These maximum strains are narrowly confined and independent of particle composition. From measurements, hoop strain above the level of the particle become larger with increasing particle mass. We propose a theoretical model that assumes the particle to be a rigid body, and estimate tube responses from the change in area due to the particle’s presence rather than a dependence on particle material. With similar conditions as in experiments, numerical simulations, performed using the software AUTODYN, revealed that the particle motion initiated a reflected pressure wave and created another pressure wave underneath the particle. The transients propagating around the particle are independent of particle material, but composition does affect the attenuation of the reflected pressure wave above the particle.

Active Air Control System Development Using Charge Air Integrated Manifold Engine Numerical Simulation (CAIMENS)

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Diana K. Grauer ◽  
Kirby S. Chapman ◽  
Ali Keshavarz
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Pressure Wave ◽  
Peak Pressure ◽  
System Development ◽  
Intake Manifold ◽  
Before And After ◽  
Mass Fractions ◽  
Pulsation Model ◽  
The Impact

This paper reports on an investigation into the transient, compressible flow physics that impact the trapped equivalence ratio. A comprehensive, variable geometry, multicylinder turbocharger-reciprocating engine computer simulation (T-RECS) has been developed to illustrate the effect of airflow imbalance on an engine. A new model, the charge air integrated manifold engine numerical simulation (CAIMENS), is a manifold flow model coupled with the T-RECS engine processor that uses an integrated set of fundamental principles to determine the crank angle-resolved pressure, temperature, burned and unburned mass fractions, and gas exchange rates for the cylinder. CAIMENS has the ability to show the transient impact of one cylinder firing on each successive cylinder. The pulsation model also describes the impact of manifold pressure drop on in-cylinder peak pressure and the pressure wave introduced to the intake manifold by uncovering the intake ports. CAIMENS provides the information necessary to quantify the impact of airflow imbalance, and allows for the visualization of the engine system before and after airflow correction. The model shows that not only does the manifold pressure drop have a significant impact on the in-cylinder peak pressure but it also has an impact on the pressure wave introduced to the intake manifold as the ports are opened. Also, each cylinder has a considerable impact on the airflow into each successive cylinder.

scholarly journals Pressure Wave Caused by Trinitrotoluene (TNT) Underwater Explosion—Short Review

2020 ◽  
Vol 10 (10) ◽  
pp. 3433
Author(s):  
Radosław Kiciński ◽  
Bogdan Szturomski
Keyword(s):  
Pressure Wave ◽  
Time Course ◽  
Underwater Explosion ◽  
Computer Hardware ◽  
Acoustic Medium ◽  
Computational Techniques ◽  
Pressure Waves ◽  
Underwater Explosions ◽  
Mesh Density ◽  
The Impact

The development of computational techniques and computer hardware has an impact the analysis of short-term (fast-changing) processes, such as the impact of a non-contact underwater explosion pressure waves. A theory of underwater explosions, gas bubble formation and pressure waves are presented. The course of the pressure wave in time, and its propagation in the acoustic medium are presented. The study presents empirical descriptions of non-contact pressure explosion waves. We propose to use them in simulations of ship hull strength and other objects immersed in liquids that are exposed to the effects of non-contact trinitrotoluene (TNT)-charge explosions. Pressure distributions and their time courses given by authors such as R.H. Cole, J.S. Nawagin, W. Stiepanow, T.E. Farley and H.G. Snay, T.L. Geers and K.S. Hunter are compared. A method of pressure wave modeling using acoustic media implemented in Computer Aided Engineering (CAE) programs is presented. The results of the values and the time course of the pressure acting on the underwater object are given. The influence of FEM (Finite Element Method) mesh density on the obtained results is examined and presented. The aim of the article is to expand our knowledge of underwater explosions, compare mathematical descriptions of the pressure waves developed by different authors and show the differences between them. In addition, we present the distinction between contact and non-contact explosions and analyze how changes in the mesh density of acoustic elements affects the reflection of the incident wave caused by an underwater explosion.

scholarly journals Characterization of a Setup to test the Impact of High-Amplitude Pressure Waves on Living Cells

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Mischa Schmidt ◽  
Ulf Kahlert ◽  
Johanna Wessolleck ◽  
Donata Maciaczyk ◽  
Benjamin Merkt ◽  
...  
Keyword(s):  
High Amplitude ◽  
Living Cells ◽  
Pressure Waves ◽  
The Impact

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

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