Analysis Of Pressure Field Research Articles

Numerical analysis of the pressure field on curved and open self-weighted metallic roofs due to the wind effect by the finite volume method

In this paper, an evaluation of distribution of the air pressure is determined throughout the curved and open self-weighted metallic roof due to the wind effect by the finite volume method. Data from experimental tests carried out in a wind tunnel involving a reduced scale model of a roof as well as our previous results using the finite element method (FEM) [J.J. del Coz, P.J. García Nieto, F.J. Suárez Domínguez, Numerical analysis of pressure field on curved self-weighted metallic roofs due to wind effect by the finite element method, J. Comput. Appl. Math. 192 (1) (2006) 40–50.] were used for comparison. The nonlinearity is due to Navier–Stokes equations that govern the turbulent flow. The calculation has been carried out keeping in mind the possibility of turbulent flow in the vicinities of the walls, and speeds of wind have been analyzed understood between 30 and 40 m/s. Finally the forces and moments are determined on the cover, as well as the distribution of pressures on the same one, comparing the results obtained with the Spanish and European Standards rules, given place to the conclusions that are exposed in the study.

Pressure field analysis on oscillating circular cylinder

Abstract The flow–structure interaction of an oscillating circular cylinder in the synchronization field at sub-critical Reynolds number is still an open research point, both in terms of experimental description and in terms of available numerical simulation models. The complexity of the problem is mainly due to the relevant nonlinear effects induced by the oscillating cylinder on the flow field. Evidence of this is given by the possible co-existence of different solutions to the nonstationary fluid-dynamic problem, switching from one to the other depending on minor changes in the key nondimensional parameters governing the phenomenon (nondimensional oscillation amplitude and critical velocity ratio). The tests described have been realized in air using a rigid model elastically suspended and instrumented by an on-board high frequency response pressure scanner. The instantaneous pressure distribution on a cylinder section has been measured allowing identification of different vortex shedding states and calculation of aerodynamic integral forces on the cylinder and their correlation with the motion time histories.

Experimental and Numerical Study on the Melting Acceleration of Phase Change Material by Ultrasonic Vibrations

The present study was investigated on the melting phenomena and the accelerative factors of phase change material (PCM) by acoustic streaming induced ultrasonic vibrations. To investigate the melting phenomena and accelerative factors, the experimental study was measured the liquid temperature and melting time of PCM and was observed the velocity vectors and thermal fluid flow induced acoustic streaming to investigate the heat transfer using particle image velocimetry (PIV) and infrared thermo vision camera, respectively. Also, the numerical study based on a coupled finite element-boundary element method (Coupled FE-BEM) was performed to investigate the analysis of pressure field in the PCM. The results of experimental works revealed that acoustic streaming observed by PIV and infrared thermo vision camera is one of the prime effects accelerating phase change heat transfer. And, the final temperature of PCM is lower and melting speed is 2.6 times faster than that without ultrasonic vibrations when ultrasonic vibrations are applied. The results of numerical work presented that acoustic pressure is higher near the ultrasonic transducer than other points where no ultrasonic transducer was installed and develops more intensive flow such as acoustic streaming, destroying the flow instability. Moreover, the profile of acoustic pressure variation is consistent with that of enhancement of heat transfer.

Numerical analysis of pressure field on curved self-weighted metallic roofs due to the wind effect by the finite element method

In this paper, an evaluation of distribution of the air pressure is determined throughout the curved and open self-weighted metallic roof due to the wind effect by the finite element method (FEM) [K. Bathe, Finite Element Procedures, Prentice-Hall, Englewood Cliffs, New York, 1996]. Data from experimental tests carried out in a wind tunnel involving a reduced scale model of a roof was used for comparison. The nonlinearity is due to time-averaged Navier–Stokes equations [C.A.J. Fletcher, Computational Techniques for Fluid Dynamics, Springer, Berlin, 1991] that govern the turbulent flow. The calculation has been carried out keeping in mind the possibility of turbulent flow in the vicinities of the walls, and speeds of wind have been analyzed between 30 and 40 m/s. Finally, the forces and moments are determined on the cover, as well as the distribution of pressures on the same one, comparing the results obtained with the Spanish and European Standards rules, giving place to the conclusions that are exposed in the study.

Dynamic Characteristics of Sealed Squeeze Film Damper With a Central Feeding Groove

In this paper, the dynamic characteristics of an oil-lubricated, sealed squeeze film damper (SFD) with a central feeding groove are analytically derived based on an enhanced dynamic pressure field analysis, accounting for the effect of the seal and feeding grooves, and its validity is experimentally verified. A test rig using an active magnetic bearing system as an exciter is introduced to identify the dynamic characteristics of SFDs with high accuracy and efficiency. Experiments are conducted with the seal gap varied, in order to investigate its effect on the dynamic characteristics of the SFD. The estimated and analytical damping and inertia coefficients for the sealed SFD with a groove are compared and it is found that the pressure field analysis, when neglecting the effect of the seal groove, tends to far underestimate the SFD dynamic coefficients.

Analysis of the wind field and heat budget in an alpine lake basin during summertime fair weather conditions

¶Observational data collected in the Lake Tekapo hydro catchment of the Southern Alps in New Zealand are used to analyse the wind and temperature fields in the alpine lake basin during summertime fair weather conditions. Measurements from surface stations, pilot balloon and tethersonde soundings, Doppler sodar and an instrumented light aircraft provide evidence of multi-scale interacting wind systems, ranging from microscale slope winds to mesoscale coast-to-basin flows. Thermal forcing of the winds occurred due to differential heating as a consequence of orography and heterogeneous surface features, which is quantified by heat budget and pressure field analysis.

724 - Shock Wave Lithotripter Pressure Field Analysis

No AccessJournal of Urology1 Jun 1987Shock Wave Lithotripter Pressure Field Analysis Frank P. Begun, Stephen C. Jacobs, and Russel K. Lawsan Frank P. BegunFrank P. Begun More articles by this author , Stephen C. JacobsStephen C. Jacobs More articles by this author , and Russel K. LawsanRussel K. Lawsan More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(17)75874-0AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "Shock Wave Lithotripter Pressure Field Analysis." The Journal of Urology, 137(6), p. 285A © 1987 by The American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 137Issue 6June 1987Page: 285A Advertisement Copyright & Permissions© 1987 by The American Urological Association Education and Research, Inc.MetricsAuthor Information Frank P. Begun More articles by this author Stephen C. Jacobs More articles by this author Russel K. Lawsan More articles by this author Expand All Advertisement Loading ...

Pressure Field and Core Barrel Loadings during Pressurized Water Reactor Blowdown

A set of computer codes based on different physical models has been developed for the investigation of effects that are essential for the analysis of pressure fields and structural loads and responses during pressurized water reactor (PWR) blowdown. The main aspects under investigation are: (1) two- and three-dimensionality, nonequilibrium two-phase flow; (2) advanced structural models; and (3) fluid-structure interaction. The goal of separate investigation of these aspects is to establish guidelines for the development of an integrated model. Which effects must be represented. Which effects should be neglected because they only insignificantly influence the result. Some of the results of these investigations are as follows: two- and (in certain areas) three-dimensional representation of the fluid flow and pressure field is essential in the PWR downcomer. Fluid structural coupling is an effect that must be taken into account. The structural model must be able to resolve the steep pressure gradients in the neighborhood of the broken nozzle. Homogeneous equilibrium two-phase models are adequate except in the immediate vicinity of the broken nozzle.

Nonlinear analysis of pressure field upstream of transonic rotors and generation of combination tones

Pressure field upstream of a transonic rotor with attached shock waves is determined using the rotational method of characteristic. In addition to the theoretical case of rotors with identical blades, the analysis includus the practical case of rotors with blade-to-blade variations due to manufacturing tolerances. The variations are produced in the analysis by assuming perturbations in the blade stagger angle and radius of curvature at the leading edge. Perturbation at one blade is shown to significantly modify the pressure field only at the following two blade channels. Investigations of static pressure waves upstream of the rotor with errors in neighboring blades indicate that the effects of manufacturing errors in the blades are linearly additive. Influence functions for errors in blade stagger angle have been deduced and the pressure pattern due to variety of error configurations has been obtained. Rotation of these pressure patterns results in noise spectra at blade passage frequency and multiples of the shaft rotation frequency, with the manufacturing errors inducing frequency and amplitude modulation effects. The relative intensity of the various harmonics is shown to be dependent on error configurations and the axial location upstream of the rotor. Correlated and uncorrelated error distributions are considered. Comparison with available experimental data, however, indicates that blade errors in actual rotors are essentially uncorrelated.