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CFD Validation Experiment of a Mach 2.5 Axisymmetric Shock-Wave Boundary-Layer Interaction

CFD Validation Experiment of a Mach 2.5 Axisymmetric Shock-Wave Boundary-Layer Interaction

Flow through Test Section with Shock Interaction The final set of preliminary measurements was performed with the two shock generator configurations shown in Figure 10. The wall static pressure distributions on the upper (AA) and lower (BB) positions are shown for the 10.0° and 13.5° shock generators in Figure 22a and Figure 22b, respectively. To estimate the shock impingement location, surface flow visualization was performed using an oil and florescent dye mixture. These results are shown at the top of the figures. For both cases, symmetry between the upper and lower pressure tap positions is observed to be quite good. As anticipated, the interaction region for both cases is located in the vicinity of the window centerline. The magnitude of the peak pressure and the axial extent of the interaction region is, as expected, greater for the stronger interaction case. For the 10.0° case, the oil flow shows a light line indicating the upstream influence of the shock impingement, but no flow separation appears to be present. This line also corresponds with the initial rise in wall pressure. For the 13.5° case, the oil flow shows a small pooling of oil indicating flow separation. The upstream edge of the pooling also corresponds with the initial rise in wall pressure.
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Earthquake-Induced Soil Pressures on Structures

Earthquake-Induced Soil Pressures on Structures

45 • • • 53 Force and moment on smooth rigid wall for one-g static horizontal body force 54 2.7 Finite element mesh for static solutions 57 2.8 Pressure distributions on rigid wall for o[r]

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Model validation for flow and heat 
		transfer characteristics of supercritical CO2 in mini channels

Model validation for flow and heat transfer characteristics of supercritical CO2 in mini channels

From the numerical analysis, the temperature distributions, heat transfer coefficient and pressure drop were obtained from data collected through total pressures, outer and inner wall static temperatures, and surface heat transfer coefficients. These data were analyzed and compared with the experimental data from Liao and Zhao (Liao and Zhao 2002). Then, the temperature, heat transfer coefficients, and pressure drop were determined.

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3D Computational Fluid Dynamics of a Treated Vertebrobasilar Giant Aneurysm: A Multistage Analysis

3D Computational Fluid Dynamics of a Treated Vertebrobasilar Giant Aneurysm: A Multistage Analysis

An extensive postmortem examination of a fixed adult cadaveric specimen with a VBJ giant aneurysm is presented. The aneurysm was characterized radiographically by DSA and CT angiography and was treated with endovascular embolization. First, a 4.5- mm ⫻ 20-mm Neuroform stent (Boston Scientific, Natick, Mas- sachusetts) was placed across the neck of the aneurysm. One month later, the aneurysm was filled with 11 Guglielmi detach- able coils-18 (Boston Scientific) (Fig 1A–D). Then, 5 months later, recanalization of the aneurysm occurred (Fig 1E). The coil mass was compacted and shifted to the superior portion of the dome. There was a filling, measuring 40 ⫻ 35 mm, along the right wall of the lesion, in the proximity of the aneurysm neck. The aneurysm was, again, endosaccularly embolized— 4 Guglielmi detachable coils-18 were used to create a scaffold inside the re-
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A study on turbulence transportation and modification of Spalart–Allmaras model for shock-wave/turbulent boundary layer interaction flow

A study on turbulence transportation and modification of Spalart–Allmaras model for shock-wave/turbulent boundary layer interaction flow

Impinging shock-wave/turbulent boundary layer interaction and compression ramp flow (see Fig. 1) are two of classic and challengeable 2D SWTBLI flow. 21 In our work, FLUENT (commercial software for CFD) is employed to investigate the performance of the modified S–A (MSA) model. The modified model is implemented by taking user-defined function (UDF) into the module. Steady simulation is carried out with the finite volume method. A second-upwind scheme is applied for the con- vection terms and grid independence is checked. The distance between the first grid line and the solid wall is set to y + < 1. 4.1. Impinging shock-wave/turbulent boundary layer interaction
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Static and Dynamic Analysis of a Concrete Shear-Wall

Static and Dynamic Analysis of a Concrete Shear-Wall

Many structures built under the earthquake resistant design were severely damaged in Loma Prieta(1989), Northridge(1994), and Kobe(1995) earthquakes. Current design trend is to limit the maximum displacement under the load. To evaluate the effectiveness of the displacement control under the near-field ground motion due to earthquake, IAEA initiated CRP program. In this paper, we try to regenerate the test results of the CRP program using ABAQUS, a general purpose nonlinear FE program, and compare the result with previous calculations. The model of the concrete shear wall came from the previous report KINS/GR317. A dynamic analysis on this model resulted in the 3 initial modes of the structure, which are similar to the modes of beam-stick model in that report. To describe the response of the concrete structure more precisely, more calibrations are necessary.
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CFD ANALYSIS OF STATIC PRESSURE AND DYNAMIC PRESSURE FOR NACA 4412

CFD ANALYSIS OF STATIC PRESSURE AND DYNAMIC PRESSURE FOR NACA 4412

It is important to study static and dynamic pressure contours on an airfoil at Vsound with varying angle of attacks to understand the impacts on lift and stagnation point. The sum of static and dynamic pressure is the total pressure, and its difference on the upper and lower surface of the airfoil is the cause of lift.

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Study of Supersonic Flow around Tandem Cavities

Study of Supersonic Flow around Tandem Cavities

Cavity flows is a wide area of research due to its flow complexities, also it finds its application in high speed vehicles such as in weapon bays, landing gears, flame holding devices in scramjet and in analysis of multi row discs. Cavity is also formed as unavoidable result of deflection of flaps of the aircraft or in pipe fittings. Cavities also have lots of applications in flame holders for combustors due to their remarkable potential to stabilize the process of combustion without any major loss in total pressure. Hence, due to its widespread use and unavoidable presence it thus becomes very important to study the flow in it, so that, any kind of disturbance and resulting damages can be avoided. As it has been seen that cavities are usually present in tandem and also the supersonic flow creates the most complexities in these cavities therefore the subsequent paper deals with both these conditions. Supersonic flows in cavities are complex due to formation of vortices, shock waves, expansion
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CFD Analysis of Twin Jet Flow At Mach 1.74 with Fluent Software

CFD Analysis of Twin Jet Flow At Mach 1.74 with Fluent Software

point, the Mach number distribution in the jet of twin jet group is totally different from that of single jet. The reason for the difference is that the single jet is axi-symmetric throughout, whereas the jets in twin jet are influenced by the wave pattern which tries to establish a slip stream right from the merging point. In the flow direction, the twin and four jets are clearly separated near the nozzle exits. Away from this region, the two jets interact, and then the two jets mix and merge to appear as a single jet. The velocity and turbulent energy profiles are fairly symmetrical around the centre line of the two and four jets for various Mach number and pressure ratio and the spacing between the two nozzles. The velocities between the two jets change along the lateral direction. The interference between two jets increases with increase of L. The stronger the interference is, the larger the Reynolds shear stress and turbulent energy are. The interference between the two jets increases as the spacing between two nozzles decrease. Furthermore the width of the twin jets spreads linearly downstream and grows with B. The merging length of the two jets can be increased either by reducing B or increasing Mach number. The results are in good agreement with the results obtained by the other techniques.
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Development of a novel film cooling hole geometry

Development of a novel film cooling hole geometry

towards the surface. For a high momentum ratio of 4.0 (Figure 2.4b) the jet is only weakly affected by the mainstream flow and penetrates into the mainstream before it is bent over. A complicated three-dimensional separation region forms downstream of the jet in both instances and, particularly for the high momentum flux ratio case, conservation of mass can cause a reversed flow region near the wall immediately downstream of the jet which entrains mainstream flow. This effect has been shown by many authors (e.g. Goldstein et al 1968, Martinez-Botas and Yuen, 2000) to cause a maximum in adiabatic effectiveness with increasing momentum flux ratio, due to what is termed “jet lift-off”. Pietrzyk et al (1989) present detailed measurements of the velocity components for a row of jets issuing into mainstream flow, measured using Laser-Doppler anemometry. The results show that while the jet structure is still clearly distinguishable ten diameters downstream there is a major enhancement of turbulence structures downstream of the jet.
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The Key Roles of Negative Pressure Breathing and Exercise in the Development of Interstitial Pulmonary Edema in Professional Male SCUBA Divers

The Key Roles of Negative Pressure Breathing and Exercise in the Development of Interstitial Pulmonary Edema in Professional Male SCUBA Divers

The study only included 16 individuals but because of the crossover design, with each individual examined in eight different conditions, we were able to produce highly statistically significant results. The study was not blinded to the participants or ultrasonographer but was analyzed in a blind fashion by an independent re- searcher. Our study did not determine the effects of depth of a dive; the effects of depth may be important because the gas density is an important determinant of breathing work [29, 30, 32]. Scores of lung comet tails have also been found to be increased at the end of apnea dives either at depth or close to surface when “struggling” inspiratory efforts developed [53]. In the latter study, a 50-m dive apnea caused compressive re- duction of lung gas volume and a very large increase in thoracic blood volume. Diaphragmatic contractions during free diving cause lowering of airways and medi- astinal pressure similar to the negative transpulmonary pressure breathing seen in our study. It can be sur- mised that the markedly larger increase in lung comet score found in our study compared with in the apnea diving study was due to the combination of several hemodynamic consequences of negative transpulmon- ary pressure with larger tidal volumes and of a longer duration. We only investigated men; we are not able to comment on the effects in women. We were unable to determine the independent effects of natriuretic pep- tides. Right ventricular fraction area change was used instead of the ejection fraction because of the difficul- ties in calculating the latter by echocardiography. We did not look for the presence of patent foramen ovale in our subjects despite its hypothetical protection from pulmonary edema.
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CFD Analysis of Four Jet Flow at Mach 1.74 with Fluent Software - Volume 1 Number 4 (Dec. 2010) - IJCEA

CFD Analysis of Four Jet Flow at Mach 1.74 with Fluent Software - Volume 1 Number 4 (Dec. 2010) - IJCEA

Bouderah, Gasmi and Serguine [12], studied on ‘Zero Gravity of Free-Surface Jet Flow’ the flow due to a jet against infinite vertical plate on the free surface, where the effects of gravity and surface tension is not taken into account. We use initially the method of the free streamline theory based on the hodograph method and Schwarz- Christoffel transformation technique to obtain the exact solution. The problem of determining the free surface due to a jet against a vertical plate is considered. The classical problem of free streamline flow of an ideal fluid has been studied by many authors. The first work in this type of problem is characterized by the use of the Schwartz- Christoffel formula. The latter can treat the flows of border, which combines rectilinear paroies and a free surface. A two dimensional flow of a jet ideal fluid encroaching on a wall neglecting the forces of gravity studied by Peng and Parker using the integral equations method. YIN Zhao-qin[13], studied on, ‘Experimental Study on The Flow Field Characteristics in the Mixing Region of Twin Jets’, twin jets flow, generated by two identical parallel axi-symmetric nozzles, has been experimentally investigated. The dimensionless spacing (B) between two nozzles were set at 1.89, 1.75 and 1.5. Measurements have been carried out at several free-stream velocities ranging from 10 m/s to 25 m/s or Reynolds numbers (based on the nozzle diameter of 44 mm) ranging from 3.33×104 to 8.33×104. The results show that the twin jets attract each other. With the increasing Reynolds number, the turbulence energy grows, which indicates that the twin jets attract acutely. The jet flow field and the merging process of two jets vary with B. The width of the twin jets flow spreads linearly downstream and grows with B. The merging between two jets occurs at the location closer to the nozzle exit for the cases with smaller spacing between nozzles and higher Reynolds number.
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Numerical Simulation of Flow through a Centrifugal Impeller

Numerical Simulation of Flow through a Centrifugal Impeller

Dean and Senoo [5] proposed the “jet and wake” model of an impeller channel flow to account for large losses taking place at the entrance of the diffuser. They revealed that mixing of flow at the impeller’s exit typically occur within a smaller radius ratio. Innoue [6] analyzed each term of the equations given by Dean and Senoo [5], and Johnson and Dean [7] to state the reasons for these theory predicting alike total pressure losses. Later, Eckardt [2, 3] with experimental results obtained by L2F velocimeter, showed the formation of the “jet-wake” structures from a nearly uniform inlet flow field to an exit flow field which was extremely distorted. A split up of sharp stable velocity gradients exist between wake and the through flow. Jet-wake structures at impeller exit, as highlighted by Hartmut Krain [8], were consequence of complex non-linear combinations involving deceleration rate of flow through impeller, flow rates, shroud cover presence, curvature and number of blades, blade exit angle, and impeller speed. Interestingly, Fowler [1] also noticed the presence of vortices in the flow field due to change of flow from axial direction to radial and the uniform flow getting into the impeller being forced towards pressure side of the flow channel due to centrifugal force, which was accelerated by the coriolis component of acceleration.
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Prediction on Turbulent Flow of Two Parallel Plane Jets Using κ ε Model

Prediction on Turbulent Flow of Two Parallel Plane Jets Using κ ε Model

ciently away from the origin of the jet, it is termed as free jet. A bounded jet will occur when the flow interacts with a parallel wall. It can be classified into three types based on the orientation: (a) Impinging jet aimed toward the boundary; (b) Wall jet where fuid is discharged at the boundary; and (c) Offset jet from a ver- tical wall of a stagnent pool issuing parallel to a horizontal solid wall. Two paral- lel plane jets have numerous technological applications such as the gas turbine combustion chamber, the air conditioner unit for automobile, the air curtain unit for refrigerator system, entrainment and mixing processes in boiler, injec- tion systems and so on. In environmental fluid mechanics, an optimum spacing between exhaust stacks (chimneys) is required to dilute disposal plums to a spe- cified level within a given from the chimney. The details of the flow was studied by several authors. The first detail experimental study of the mean flow was re- ported by Tanaka [1] [2]. He described the basic flow patterns and entrainment mechanism of parallel jets. Elbanna et al . [3] showed that the mean velocity pro- file of the parallel jets agreed well with the single jet in the region downstream of the combined point. Lin et al . [4] [5] used hot-wire anemometry to show that the mean velocity approaches self-preservation in both the merging and combined regions, while Reynolds shear stresses approach self-preservation in the com- bined region only. Nasr et al . [6] [7] provided an experimental comparison be- tween parallel, plane jets and an off set jet (where a wall replaces the symmetry plane). In a later work, they performed an experimental investigation into the effect of jet spacing on the mean stream-wise momentum flux measured at the combined point. Anderson et al . [8] presented experimental and numerical re- sults for isothermal, plane parallel jets at spacings/w = 9, 13, and 18.25 (where s is the spacing between jet centre lines and w is the jet width.). Computations of the two parallel plane jets performed by Militzer, J. [9] showed that the basic κ ε − model does not take into account the effects of stream line curvature and hence led to quite an unreasonable prediction of flow characteristics. Lechziner et al . [10] considered both the effect of streamline curvature and preferential in- fluence of normal stresses on the dissipation of turbulence energy. Nasr et al . [11] compared the obtained numerical results with experiment for the case of a turbulent plane offset jet.
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Review Paper on Static Analysis and Design of Retaining Wall with and without Shelve using Software

Review Paper on Static Analysis and Design of Retaining Wall with and without Shelve using Software

This chapter concerned with stability of the cantilever retaining wall without shelves. The stability check for cantilever retaining wall without shelves is very important to study. The principle of design of cantilever retaining wall without shelves, various forces are acting on structure and the stability of cantilever retaining wall should be checked for sliding, overturning, bearing capacity failure, and tension has been explained below,

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Static And Dynamic Analysis Of Composite Pressure Vessel

Static And Dynamic Analysis Of Composite Pressure Vessel

constant help. Without seeing that the effect of SSI. In the following case, the constructing is analysed with bendy technique i.E. Having spring base stipulations, that's incorporating the effect of flexibility of soil, the footing is believed to be resting on elastic medium. In this case six springs, one to accommodate the vertical motion, two to comprise the translational motion in corresponding horizontal instructions and three rotational springs are furnished at the groundwork stage. Within the 0.33 case ,the building is analysed without shear wall and with out SSI. The stiffness of the springs is calculated using the members of the family given via Richart et.Al.(1970). Thirdly the difference between the circumstances is when put next with each other on the bases of axial forces, bending moments, shear drive, storey float and time period. The present work offers with three D multi-bay reinforced concrete constructing situated on footings resting onunfastened soil. The connection between columns and footings will also be either constant or constant but spring. Nonetheless, it'sassumed that the soil offers flexibility to the vertical displacement, horizontal displacement and rotation on thenodded facets on the original interface between the
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Modelling of tsunami-like wave run-up, breaking and impact on a vertical wall by SPH method

Modelling of tsunami-like wave run-up, breaking and impact on a vertical wall by SPH method

Abstract. Accurate predictions of wave run-up and run- down are important for coastal impact assessment of rela- tively long waves such as tsunami or storm waves. Wave run- up is, however, a complex process involving nonlinear build- up of the wave front, intensive wave breaking and strong tur- bulent flow, making the numerical approximation challeng- ing. Recent advanced modelling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on a vertical wall using two methods, an enhanced smoothed particle hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that was observed in the experiments. Whereas the SPH method successfully simulates the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave break- ing could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows po- tential applications for accurate impact assessments of wave run-up on to coastal structures.
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Flow Behaiviour Over Supercritical Aerofoil Respective to NACA Aerofoil

Flow Behaiviour Over Supercritical Aerofoil Respective to NACA Aerofoil

---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - In aviation dynamic developments are being done to enhance the performance of aircraft wing design and hence lift and drag characteristics. Fundamental objective of this research is to compare the aerodynamics characteristics and demonstrating the superiority of supercritical aerofoil SC20410 over NACA0010 aerofoil and its advantages over NACA. For this purpose distribution of pressure over the top surface of supercritical aerofoil SC20410 and NACA0010 airfoil at different mach number has been analyzed with the help of ANSYS design modular. The meshing is done by using ANSYS ICEM CFD, which is software pack used for CAD analysis and generation of mesh. The meshed model is imported in ANSYS CFX. We will see in this research how coefficient of drag decrease and coefficient of lift increase as we increase the mach number for two different aerofoil NACA0010 and SC20410 .
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Performance and Internal Flow of Contra Rotating Small Sized Cooling Fan

Performance and Internal Flow of Contra Rotating Small Sized Cooling Fan

High pressure and large flow rate small-sized cooling fans are used for servers in data centers and there is a strong demand to increase its performance be- cause of increase of quantity of heat from servers. Contra-rotating rotors have been adopted for some of high pressure and large flow rate cooling fans to meet the demand. The performance curve of the contra-rotating small-sized cooling fan with 40 mm square casing was investigated by an experimental apparatus and its internal flow condition was clarified by the numerical analy- sis. The fan static pressure of the front rotor was extremely low and it in- creased significantly at the rear rotor. The uniform flow was achieved at the inlet of the rear rotor because of the special shape of the casing between the front and rear rotors. On the other hand, the tip leakage flow was large enough to influence on the main flow of the test cooling fan by the design specification of high pressure with compact rotor diameter.
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AERODYNAMIC ANALYSIS OF SUPERCRITICAL NACA SC (2)-0714 AIRFOIL USING CFD

AERODYNAMIC ANALYSIS OF SUPERCRITICAL NACA SC (2)-0714 AIRFOIL USING CFD

The figure 7 shows that the contours of static pressure at the airfoil wall and center domain of the airfoil. It shows that the maximum pressure is appeared in plane is 69675.74pascal and pressure appeared at leading edge is 29648.28pascal and the pressure appeared at trailing edge is -4747.38pascal, the average pressure around the airfoil wall is -1881.45pascal and Pressure Drag is 34395.65pascal. The static pressure at lower surface of the airfoil wall 2963.31pascal and at upper surface is -7710.69pascal so the Lift of the airfoil is more and this angle is optimized.
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