A Comparison of Theoretical and Experimental Pressure Distributions on Bodies of Revolution

1980 ◽  
Vol 24 (01) ◽  
pp. 60-65
Author(s):  
A. J. Smits ◽  
S. P. Law ◽  
P. N. Joubert
Keyword(s):  
Calculation Method ◽  
The Body ◽  
Viscous Effects ◽  
Bodies Of Revolution ◽  
Pressure Distributions ◽  
Wide Range ◽  
The Right ◽  
Right Order ◽  
Axisymmetric Bodies ◽  
Experimental Pressure

A wide range of experimental pressure distributions along axisymmetric bodies was compared with the results of Landweber's potential flow calculation method. Apart from certain viscous effects, some discrepancies were found, and it is shown that blockage corrections are of the right order to account for these discrepancies. The calculation method was also used to show that the pressure distribution over the nose of the body is largely independent of the tail shape, and vice versa.

Determination of Three-Dimensional Body Forms from Given Pressure Distribution Over Their Surfaces

1996 ◽  
Vol 40 (01) ◽  
pp. 22-27
Author(s):  
V. M. Pashin ◽  
V. A. Bushkovsky ◽  
E. L. Amromin
Keyword(s):  
Pressure Distribution ◽  
Three Dimensional ◽  
Bodies Of Revolution ◽  
Design Constraints ◽  
Pressure Distributions ◽  
Axisymmetric Bodies

A method for solving inverse three-dimensional problems in hydromechanics is proposed which makes it possible to fit desired pressure distributions within design constraints immediately in the course of calculations. Examples of the method of application are given for bodies of revolution in flows at nonzero drift angles. These flows are not axisymmetric. Bodies of revolution in them are very handy examples of demonstrations of the method, and these examples have many technical applications.

scholarly journals Dynamics of Attached Cavities on Bodies of Revolution

1992 ◽  
Vol 114 (1) ◽  
pp. 93-99 ◽  
Author(s):  
S. L. Ceccio ◽  
C. E. Brennen
Keyword(s):  
Reynolds Numbers ◽  
Cavitation Number ◽  
The Body ◽  
Cavity Surface ◽  
Bodies Of Revolution ◽  
The Mean ◽  
Cavity Thickness ◽  
Cavity Closure ◽  
Axisymmetric Bodies ◽  
Single Cavity

Attached cavitation was generated on two axisymmetric bodies, a Schiebe body and a modified ellipsoidal body (the I. T. T. C. body), both with a 50.8 mm diameter. Tests were conducted for a range of cavitation numbers and for Reynolds numbers in the range of Re = 4.4 × 105 to 4.8 × 105. Partially stable cavities were observed. The steady and dynamic volume fluctuations of the cavities were recorded through measurements of the local fluid impedance near the cavitating surface suing a series of flush mounted electrodes. These data were combined with photographic observations. On the Schiebe body, the cavitation was observed to form a series of incipient spot cavities which developed into a single cavity as the cavitation number was lowered. The incipient cavities were observed to fluctuate at distinct frequencies. Cavities on the I. T. T. C. started as a single patch on the upper surface of the body which grew to envelope the entire circumference of the body as the cavitation number was lowered. These cavities also fluctuated at distinct frequencies associated with oscillations of the cavity closure region. The cavities fluctuated with Strouhal numbers (based on the mean cavity thickness) in the range of St = 0.002 to 0.02, which are approximately one tenth the value of Strouhal numbers associated with Ka´rma´n vortex shedding. The fluctuation of these stabilized partial cavities may be related to periodic break off and filling in the cavity closure region and to periodic entrainment of the cavity vapor. Cavities on both headforms exhibited surface striations in the streamwise direction near the point of cavity formation, and a frothy mixture of vapor and liquid was detected under the turbulent cavity surface. As the cavities became fully developed, the signal generated by the frothy mixture increased in magnitude with frequencies in the range of 0 to 50 Hz.

scholarly journals Metastatic Biphasic Primitive Tumor in the Mandible of a Child

2020 ◽  
Vol 14 (03) ◽  
pp. 502-510
Author(s):  
Tiago Novaes Pinheiro ◽  
Milena Gomes Melo Leite ◽  
Fábio Arruda Bindá ◽  
André Luiz Tannus Dutra ◽  
Naelka Sarmento ◽  
...  
Keyword(s):  
Facial Asymmetry ◽  
The Body ◽  
Biological Behavior ◽  
Tubular Necrosis ◽  
Wide Range ◽  
Child Patient ◽  
Therapeutic Procedures ◽  
Mandibular Tumors ◽  
Neuroectodermal Origin ◽  
The Right

AbstractPediatric mandibular tumors present an aggressive biological behavior and difficult diagnosis. A wide range of odontogenic and nonodontogenic tumors comprise the spectrum of these lesions. We report a case of a 1-year-old male child patient showing facial asymmetry symptomatic of an expansive lesion extending throughout the body and ramus of the left hemimandible with a diameter of 8 cm. The histopathological report suggested a high-grade mucoepidermoid carcinoma (MEC), recommending further immunohistochemical investigation of the ectomesenchymal or neuroectodermal origin of the tumor cells. The patient evolved with extensive bilateral pleural effusion followed by metastasis in the middle third of the right humerus, and died 2 months after the first biopsy procedure by acute renal failure with tubular necrosis, before a final inconclusive immunohistochemical report was reached. The lack of resources for less-favored regions of Brazil impairs rapid biomolecular examinations such as immunohistochemical resulting in delay of appropriate therapeutic procedures.

Incompressible potential flow past ‘not-so-slender’ bodies of revolution at an angle of attack

1975 ◽  
Vol 70 (4) ◽  
pp. 651-661 ◽  
Author(s):  
P. Sivakrishna Prasad ◽  
N. R. Subramanian
Keyword(s):  
Velocity Potential ◽  
Angle Of Attack ◽  
The Body ◽  
Virtual Mass ◽  
Bodies Of Revolution ◽  
Exact Theory ◽  
Pressure Distributions ◽  
Ellipsoid Of Revolution ◽  
Slender Bodies ◽  
Good Agreement

Using the method of matched asymptotic expansions, an expansion of the velocity potential for steady incompressible flow has been obtained to order ε4for slender bodies of revolution at an angle of attack by representing the potential due to the body as a superposition of potentials of sources and doublets distributed along a segment of the axis inside the body excluding an interval near each end of the body. Also, expansions of the coefficients of longitudinal virtual mass and lateral virtual mass have been found. The pressure distributions over an ellipsoid of revolution of thickness ratio ε = 0·3 at zero angle of attack and at an angle of attack of 3° obtained by the present method are compared with results obtained from the exact theory and that of Van Dyke. The virtual-mass coefficients are also compared with those obtained from the exact theory and are found to be in good agreement up to ε = 0·3.

Hydrodynamic Analysis of a Horizontal Axis Marine Current Turbine With a Boundary Element Method

2008 ◽  
Author(s):  
J. Baltazar ◽  
J. A. C. Falca˜o de Campos
Keyword(s):  
Horizontal Axis ◽  
Model Parameters ◽  
Viscous Effects ◽  
Pressure Distributions ◽  
Marine Current Turbine ◽  
Wide Range ◽  
Marine Current ◽  
Line Theory ◽  
Wake Model ◽  
Current Turbine

A low order potential based panel code is used to analyse the flow around the blades of a horizontal axis marine current turbine. An empirical vortex model is assumed for the turbine wake which includes the variation of pitch of the helicoidal vortices trailing behind the blades. The analysis is carried out for uniform inflow conditions in steady flow for a turbine with controllable pitch for two different pitch settings in a wide range of tip-speed-ratios. Grid convergence studies carried out to verify the accuracy of predicted pressure distributions and integrated forces show a fast convergence with grid refinement for this geometry. The effect of the helicoidal wake model parameters used in the analysis is found to have a strong influence in the performance curves. The results are compared with experimental data from the literature and with the lifting line theory. A discussion of viscous effects is also provided to help explaining the main discrepancies with the data.

scholarly journals Particles, Drops, and Bubbles Moving Across Sharp Interfaces and Stratified Layers

2020 ◽  
Vol 52 (1) ◽  
pp. 61-91 ◽  
Author(s):  
Jacques Magnaudet ◽  
Matthieu J. Mercier
Keyword(s):  
Relative Magnitude ◽  
Immiscible Fluids ◽  
The Body ◽  
Body Motion ◽  
Physical Parameters ◽  
Viscous Effects ◽  
Fluid Resistance ◽  
Wide Range ◽  
Deformable Bodies ◽  
Sharp Interfaces

Rigid or deformable bodies moving through continuously stratified layers or across sharp interfaces are involved in a wide variety of geophysical and engineering applications, with both miscible and immiscible fluids. In most cases, the body moves while pulling a column of fluid, in which density and possibly viscosity differ from those of the neighboring fluid. The presence of this column usually increases the fluid resistance to the relative body motion, frequently slowing down its settling or rise in a dramatic manner. This column also exhibits specific dynamics that depend on the nature of the fluids and on the various physical parameters of the system, especially the strength of the density/viscosity stratification and the relative magnitude of inertia and viscous effects. In the miscible case, as stratification increases, the wake becomes dominated by the presence of a downstream jet, which may undergo a specific instability. In immiscible fluids, the viscosity contrast combined with capillary effects may lead to strikingly different evolutions of the column, including pinch-off followed by the formation of a drop that remains attached to the body, or a massive fragmentation phenomenon. This review discusses the flow organization and its consequences on the body motion under a wide range of conditions, as well as potentialities and limitations of available models aimed at predicting the body and column dynamics.

scholarly journals Problémás magánjogi elemek a helyi rendeletalkotásban

2018 ◽  
Vol 15 (3-4) ◽  
pp. 2-11
Author(s):  
Zsuzsanna Árva ◽  
Judit Szabó
Keyword(s):  
Local Governments ◽  
Civil Law ◽  
Subject Area ◽  
Public Affairs ◽  
The Body ◽  
Public Affair ◽  
First Case ◽  
Wide Range ◽  
The Right ◽  
Municipal Housing

Local governments may establish legal relationships governed by civil law in numerous ways, for example, through the creation of associations, various institutional agreements or they can also do so by means of enacting regulations. In line with the stipulations of the Fundamental Law of Hungary, local governments may adopt regulations on two legal bases: if authorized by law or if they want to regulate a local public affair; however, the regulation may not contradict any higher form of legislation. While in the first case it is not only the right but also the obligation of local governments to enact regulations that can even be sanctioned, in the second case it is almost completely optional. The scope of public affairs regulated by local governments is rather broad. While the smaller local governments typically limit their activities to the regulation of the most urgent matters, the larger local governments enact regulations in a wide range of issues also due to the volume of their responsibilities. In many instances a part of these regulations does not remain within the framework of supremacy but also includes numerous elements of civil law. These could include matters related to parking or municipal housing, as well as problems in connection with public services. Norms regulating peaceful public coexistence represent a separate subject area as in many cases they wish to regulate legal relationships pertaining to privacy. In the case of the latter issue, the clause stating that the local regulations shall not contradict any higher form of law is especially central, as it necessitates the extensive knowledge of civil and in some cases even constitutional law to ensure that such a regulation is enacted that fully complies with the laws. This paper introduces and examines those local government regulations that include elements of civil law also and which typically cause problems, with special emphasis on the rules of peaceful public coexistence. Some of these problems are revealed within the scope of legal supervision practiced over local governments, while in other cases the body reviewing the regulation acts in response to citizens’ initiatives.

A Combination of the Quasi-Cylinder and Slender Body Theories

1955 ◽  
Vol 59 (532) ◽  
pp. 305-308 ◽  
Author(s):  
C. H. E. Warren ◽  
L. E. Fraenkel
Keyword(s):  
Point Of View ◽  
The Body ◽  
Slender Body ◽  
Maximum Diameter ◽  
Slender Body Theory ◽  
Bodies Of Revolution ◽  
Pressure Distributions ◽  
Simple Body ◽  
Body Theory ◽  
Supersonic Flow Past Bodies

The Quasi-Cylinder and slender body theories for the supersonic flow past bodies of revolution have been much used in recent years because, for reasonably simple body profiles, these theories permit a simple and rapid calculation of the first-order pressure distributions and aerodynamic forces. It is assumed in both theories that the body profile slope is small; in the quasi-cylinder theory it is also assumed that the body radius is nearly constant, whereas in the slender body theory it is assumed that the thickness ratio of the body (maximum diameter/length) is small.In the present note these two theories are combined completely. From a strictly mathematical point of view nothing is gained by this combination, and, furthermore,application of the combined theory to a particular case is in general a little more laborious than application of either of the original theories.

scholarly journals Lateralized Behavior of Bottlenose Dolphins Using an Underwater Maze

2016 ◽  
Vol 29 ◽  
Author(s):  
Fay E. Clark ◽  
Stan A. Kuczaj II
Keyword(s):  
Task Complexity ◽  
Bottlenose Dolphins ◽  
The Body ◽  
Left Brain ◽  
Wide Range ◽  
Novel Objects ◽  
Eye Preference ◽  
The Right ◽  
Familiar Stimuli ◽  
The Brain

Behavior is lateralized when it is performed preferentially by one side of the body, and this phenomenon is seen across a wide range of vertebrate taxa. Furthermore the brain and body are contralateral in many animals, meaning that the left brain hemisphere most dominantly controls the right side of the body and vice versa. Lateralized behavior in humans and nonhuman primates reveals a population right-hand bias. Recent studies in primates have also begun to link differences in lateralized behavior to task complexity, and responses to novel versus familiar stimuli. Parallel research on cetaceans is sparse although evidence accrued over the last decade suggests captive dolphins have a preference for swimming counter-clockwise, a right-eye advantage in spatio-cognitive tasks and a right-eye preference for viewing novel objects, although this is the reverse of the general vertebrate pattern. Lateralized behavior was examined in a group of six male bottlenose dolphins (Tursiops truncatus) in response to a novel underwater maze, and compared to behavior during a baseline condition (no maze present). Dolphins were significantly more likely to swim counter-clockwise round their pool during both the baseline and maze condition, interpreted as a right eye bias. Swimming rotation was also weaker in dolphins during the maze condition, suggesting that the maze may have disrupted routine circular swimming behavior. There was no clear preference for using the left or right side of the maze, except in two high- using subjects with a strong right preference. Modifications and extensions to the methods are discussed.

Motoneurone Discharges to the Eyecup Muscles of the Crab carcinus

1968 ◽  
Vol 49 (2) ◽  
pp. 251-267
Author(s):  
M. BURROWS ◽  
G. A. HORRIDGE
Keyword(s):  
The Body ◽  
Muscle Fibres ◽  
Tonic Activity ◽  
Large Scatter ◽  
Absolute Position ◽  
Wide Range ◽  
Long Time ◽  
Slow Muscle Fibres ◽  
The Mean ◽  
The Right

1. During imposed tilt the eyecup or the crab tends to preserve an absolute position which depends upon the tonic activity of eight of the nine eyecup muscles. The detailed activity of all these muscles during imposed tilt in different planes has been recorded intracellularly. 2. The slow- and fast-motoneurone discharges to the eyecup muscles differ in that the former have intervals which are more variable at lower frequencies but the latter are more variable at higher frequencies. 3. The standard deviation of the interval between impulses is 20-30% of the mean interval for a wide range of frequencies of the tonic motoneurones. This large scatter is tolerable because the slow muscle fibres are sluggish and because the eyecup is also visually stabilized by a system of long time-constant. 4. In roll the two eyecups move in opposite directions relative to the midline of the animal. In pitch the two eyecups move in the same direction relative to the body of the animal, but in neither case is there a correlation between individual impulses to the muscles of the right and left eyecups which are active at the same time. 5. Possible mechanisms of linkage between the two eyecups are discussed.

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