Analytic estimation of the impact pressure in a beam-tube due to water-hammer effect

2013 ◽  
Vol 50 (12) ◽  
pp. 1139-1149 ◽  
Author(s):  
Namgyun Jeong ◽  
Daeyoung Chi ◽  
Juhyeon Yoon
Keyword(s):  
Water Hammer ◽  
Impact Pressure ◽  
Beam Tube ◽  
The Impact ◽  
Water Hammer Effect ◽  
Analytic Estimation

New Designs in Fuel Dispensing System to Reduce Water Hammer

2013 ◽  
Author(s):  
Y. J. Liu ◽  
Z. Y. Wang ◽  
Z. Y. Huang ◽  
J. Lumkes
Keyword(s):  
Working Conditions ◽  
Rate Control ◽  
Water Hammer ◽  
Service Station ◽  
Start Up ◽  
Flow Rate Control ◽  
The Impact ◽  
Water Hammer Effect ◽  
Rapid Pressure ◽  
Nozzle Structure

Dispensers are used for refueling vehicles at the service station. During the refueling process, the velocity of fluid changes rapidly in several working conditions, which results in a rapid pressure increasing or a water hammer effect occurring. Water hammer, often causes leakage or failure of dispensers, occurs due to pump start-up and shut-down, valves opening or closing during the refueling process. This paper experimentally characterized and theoretically calculated the impact of water hammer on the dispensers at the service station. New designs of nozzle structure and new flow-rate control modes are made to reduce the water hammer in the fuel dispensing system. Eventually, all the water hammers are reduced significantly during the refueling process under the new design modes.

Research on the Impact Pressure of the Hydraulic Rolling-Cut Shear

2010 ◽  
Vol 145 ◽  
pp. 410-413 ◽  
Author(s):  
Jing Wang ◽  
He Yong Han ◽  
Qing Xue Huang ◽  
Jun Wang
Keyword(s):  
Hydraulic System ◽  
Impact Pressure ◽  
Direct Impact ◽  
Actual Situation ◽  
Work Situation ◽  
Servo Valve ◽  
Indirect Impact ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
The Impact

The reasons for impact pressure are obtained by the research the hydraulic system of Hydraulic Rolling-Cut Shear. The impact pressure of hydraulic system is divided into direct impact and indirect impact. Based on analyzing the actual situation the measures should be taken to reduce the impact pressure when design hydraulic system. The suitable length of pipeline can improve the performance of the hydraulic system because the length is important for the impact pressure. The accumulator can absorb impact pressure and improve the work situation of servo valve. Therefore, the suitable accumulators should be set in the hydraulic system. The study provides theory basis for the pipe design of large hydraulic servo system.

Relation Between Flow Velocity and Impact Pressure in a Green Water Flow

2013 ◽  
Author(s):  
Kusalika Ariyarathne ◽  
Kuang-An Chang ◽  
Richard Mercier
Keyword(s):  
Kinetic Energy ◽  
Void Fraction ◽  
Pressure Rise ◽  
Impact Pressure ◽  
Breaking Wave ◽  
Wave Condition ◽  
Wall Impingement ◽  
Impact Coefficient ◽  
The Impact ◽  
Mean Kinetic Energy

Impact pressure due to plunging breaking waves impinging on a simplified model structure was investigated in the laboratory based on two breaking wave conditions: the wall impingement wave condition and the deck impingement wave condition. Pressure, void fraction, and velocities were measured at various locations on the deck surface. Impact pressure was correlated with the mean kinetic energy calculated based on the measured mean velocities and void fraction to obtain the impact coefficient. For the wall impingement wave condition, the relationship between impact pressure and mean kinetic energy is linear with the impact coefficient close to unity. For the deck impingement wave condition, the above relationship does not show good correlation, whereas the impact coefficient was found to be a function of the rate of pressure rise.

scholarly journals ELIMINATION OF IMPACT WHEN CLOSING THE DISC VALVE ON THE DRAINAGE OF HORIZONTAL SEDIMENTS

2021 ◽  
Vol 11 (1) ◽  
pp. 56-62
Author(s):  
Sergej A. ANCIFEROV ◽  
Elena V. CHIRKOVA ◽  
Mariya N. KUCHERENKO
Keyword(s):  
Numerical Experiment ◽  
Low Pressure ◽  
Water Hammer ◽  
Pneumatic Actuator ◽  
Closed Space ◽  
Additional Energy ◽  
Before And After ◽  
Treatment Facilities ◽  
The Impact

The reasons for the occurrence of an impact when closing a butt erfl y valve installed on pipelines that discharge sludge water from horizontal sedimentation tanks of treatment facilities are considered. The assumption about the possibility of water hammer was experimentally refuted. It is hypothesized that the cause of the impact is the disruption of the fl uid fl ow when fl owing around a fl at plate at critical angles of att ack. A numerical experiment was carried out, which consists in modeling the movement of a water fl ow in a completely fi lled, closed space of a pipe. As a result of the experiment, it was revealed that the fl ow stall was caused by the formation of zones of high and low pressure, respectively, before and after the valve. This provides additional energy to increase the closing torque, comparable to the force of a pneumatic actuator, and results in an impact.

scholarly journals LABORATORY OBSERVATIONS OF IMPACTS ON COARSE SEDIMENT BEACHES

2011 ◽  
Vol 1 (32) ◽  
pp. 53
Author(s):  
Ian Ball ◽  
Edgar Mendoza-Baldwin ◽  
David Simmonds ◽  
Adrián Pedrozo-Acuña ◽  
Dominic E Reeve
Keyword(s):  
Full Scale ◽  
Impact Pressure ◽  
Coarse Grained ◽  
Laboratory Measurements ◽  
Coarse Sediment ◽  
Full Scale Tests ◽  
The Impact ◽  
Impact Events ◽  
Plunging Breaker

In this paper we present laboratory observations of plunging wave breaker impact pressure responses on a steep coarse-grained beach, extending previous work conducted by Pedrozo-Acuña et al. (2008). Scale laboratory measurements of plunging breaker impact events are reported and compared with the previous full-scale tests. These tests extend the previous relationships to a wider range of surf-similarity parameters and indicate a continued reduction in impact pressure as the transition from plunging impacts to surging impacts is approached. Additional results from scale tests conducted on a smooth impermeable slope also indicate the presence of a maximum impact pressure within the plunging breaker region; however also suggest it may be necessary to include roughness and permeability in the parameterization of the impact pressure.

Spectral Analysis of Irregular Wave Impact on the Structure in Splash Zone

2002 ◽  
Author(s):  
Bing Ren ◽  
Yongxue Wang
Keyword(s):  
Spectral Analysis ◽  
Wave Height ◽  
Incident Wave ◽  
Impact Pressure ◽  
Splash Zone ◽  
Spectral Moment ◽  
Wave Impact ◽  
Large Wave ◽  
Irregular Wave ◽  
The Impact

The spectral analysis from experimental data of irregular wave impact on the structures with large dimension in the splash zone is presented. The experiments were conducted in the large wave-current tank in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. In the experiment, the target spectrum is JONSWAP spectrum, the significant wave height H1/3 is in the range from 0.1m to 0.3m, and the peak period of spectrum Tp in the range from 1.0s to 2.0s. The ratio of s/H1/3, which refers to the clearance of the subface of the structure above still water level (s) to the incident wave height, is between −0.1 and 0.4. The spectral analysis results of the irregular wave impact pressure on the subface of the structure under various case studies are presented. The distribution of spectral moment of the impact pressure on the structure along the subface is given. And the influence of different incident wave parameters and relative clearance s/H1/3 on the average spectral moment of impact pressure are discussed.

scholarly journals Seismic and Impact–Pressure Monitoring of Flowing Avalanches

1980 ◽  
Vol 26 (94) ◽  
pp. 179-187 ◽  
Author(s):  
P. A. Schaerer ◽  
A. A. Salway
Keyword(s):  
Wave Motion ◽  
Impact Pressure ◽  
Seismic Signals ◽  
Snow Avalanches ◽  
Pressure Monitoring ◽  
Surface Areas ◽  
Load Cells ◽  
Rapid Flow ◽  
The Impact ◽  
Initial Peak

AbstractContinuous records have been made during the passage of dry–snow avalanches of both seismic signals, which allows the avalanche speed to be estimated, and impact pressures on load cells with surface areas of 645 and 6 450 mm2. The impact pressure recordings show an initial peak followed by a base pressure. The observed initial and base pressures vary strongly within avalanches and from one avalanche to another, but, on average, they can be correlated with the frontal speed and the density of the deposited avalanche snow. It is concluded that well–developed dry–snow avalanches have an unsteady wave motion similar to the slug flow observed in ultra–rapid flow of water, and that they consist of three stratified components: dense flowing snow at the bottom, light flowing snow, and powder snow.

On Transition From Supersonic to Subsonic Flow at Low Reynolds Numbers in a Tube

1969 ◽  
Vol 36 (2) ◽  
pp. 146-150 ◽  
Author(s):  
R. Y. Chen ◽  
J. C. Williams
Keyword(s):  
Mach Number ◽  
Static Pressure ◽  
Subsonic Flow ◽  
Supersonic Nozzle ◽  
Reynolds Numbers ◽  
Impact Pressure ◽  
Low Reynolds Numbers ◽  
Pressure Distributions ◽  
Low Reynolds ◽  
The Impact

A supersonic low-density gas stream produced in a supersonic nozzle was passed through a circular tube in which the transition from supersonic to subsonic flow took place. Static pressure distributions along the tube (and nozzle) and impact pressure distributions across the tube at several stations were measured to determine the nature of this transition. The impact pressure distributions were used, together with the local static pressure, to infer Mach number and velocity profiles in the tube. When the pressure distributions and center-line Mach number distributions are considered together, one obtains a fairly clear picture of the processes involved in the transition from supersonic to subsonic flow at low Reynolds numbers.

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