scholarly journals Gravity analysis to estimate the mud stream direction in porong by applying the delaunay approach

2019 ◽  
Vol 311 ◽  
pp. 012067
Author(s):  
M I Putra ◽  
A N Hidayah ◽  
L A E S Septiana ◽  
E Supriyana
Keyword(s):  
Stream Direction

Large-scale structure and entrainment in the supersonic mixing layer

1995 ◽  
Vol 284 ◽  
pp. 171-216 ◽  
Author(s):  
N. T. Clemens ◽  
M. G. Mungal
Keyword(s):  
Mach Number ◽  
High Speed ◽  
Large Scale ◽  
Mixture Fraction ◽  
Mixing Layer ◽  
Mie Scattering ◽  
Planar Laser ◽  
The Cross ◽  
Convective Mach Number ◽  
Stream Direction

Experiments were conducted in a two-stream planar mixing layer at convective Mach numbers,Mc, of 0.28, 0.42, 0.50, 0.62 and 0.79. Planar laser Mie scattering (PLMS) from a condensed alcohol fog and planar laser-induced fluorescence (PLIF) of nitric oxide were used for flow visualization in the side, plan and end views. The PLIF signals were also used to characterize the turbulent mixture fraction fluctuations.Visualizations using PLMS indicate a transition in the turbulent structure from quasi-two-dimensionality at low convective Mach number, to more random three-dimensionality for$M_c\geqslant 0.62$. A transition is also observed in the core and braid regions of the spanwise rollers as the convective Mach number increases from 0.28 to 0.62. A change in the entrainment mechanism with increasing compressibility is also indicated by signal intensity profiles and perspective views of the PLMS and PLIF images. These show that atMc= 0.28 the instantaneous mixture fraction field typically exhibits a gradient in the streamwise direction, but is more uniform in the cross-stream direction. AtMc= 0.62 and 0.79, however, the mixture fraction field is more streamwise uniform and with a gradient in the cross-stream direction. This change in the composition of the structures is indicative of different entrainment motions at the different compressibility conditions. The statistical results are consistent with the qualitative observations and suggest that compressibility acts to reduce the magnitude of the mixture fraction fluctuations, particularly on the high-speed edge of the layer.

Numerical Analysis of Flow and Heat Transfer Characteristics on Micro Couette Flow

2014 ◽  
Vol 960-961 ◽  
pp. 551-554
Author(s):  
Lei Huang ◽  
Yang Cui
Keyword(s):  
Shear Stress ◽  
Couette Flow ◽  
Velocity Slip ◽  
Flow And Heat Transfer ◽  
Knudsen Numbers ◽  
Pressure Profiles ◽  
Viscous Heat ◽  
Temperature And Pressure ◽  
In The Beginning ◽  
Stream Direction

In this paper, Couette flow is mainly discussed by studying the general flow behaviour mechanism and importing the velocity slip and temperature jump boundary condition. By analyzing velocity, temperature and pressure profiles at different Knudsen numbers, we concluded that Couette flow is driven by shear stress. The shear stress lies in stream direction. Viscous heat causes the increasing of the fluid’s temperature. With the increasing of Knudsen numbers, the increasing speed increases. It’s in the beginning of transition region that the heat flux has the maximum.

18.—Sedimentation in some Scottish Rivers of Low Sinuosity

1976 ◽  
Vol 69 (18) ◽  
pp. 425-456 ◽  
Author(s):  
B. J. Bluck
Keyword(s):  
Water Level ◽  
High Flow ◽  
Sediment Type ◽  
Meandering Streams ◽  
Bed Forms ◽  
Gravel Bars ◽  
The Mean ◽  
Flow Stage ◽  
Stream Direction ◽  
Maximum Rise

SynopsisScottish streams of low sinuosity have four kinds of bars, three are bank-attached (lateral), and one is medial. Bar type is related to sinuosity, and as streams often increase in sinuosity away from source, there tends to be a variation in bar type successively downstream. The morphology and structure of the bars are related to grain size—gravel bars do not have the same bed forms and structures as those made of sand—and variations in flow stage. The bar head, composed mostly of gravel, forms during the high-flow stage, and as the flow falls so sediments of the lee face record the changing flow pattern. With further drop in water level the locus of sedimentation shifts to the bar tail where the dwindling flow may build diversely oriented bed forms and structures. Changes in the rate of fall, or differences in the maximum rise of water level, result in different proportions of sediment type being deposited.The mean orientation of the directional structures is not always alined with the mean stream direction, and the diversity of orientation is comparable with the diversity in orientation of directional structures in meandering streams. The variability in orientation is due to the effects of flood-produced bed forms in diverting the low-stage flow, stream sinuosity, and the changing orientation of the channel as it sweeps across the floodplain.

A Study of the Hydroelastic Instabilities of Supercavitating Hydrofoils

1960 ◽  
Vol 4 (04) ◽  
pp. 28-38
Author(s):  
Paul Kaplan ◽  
C. J. Henry
Keyword(s):  
Dynamic Instability ◽  
Experimental Studies ◽  
Surface Flow ◽  
Small Range ◽  
Equal Importance ◽  
Static Instability ◽  
Elastically Restrained ◽  
Density Ratios ◽  
Oscillating Foil ◽  
Stream Direction

Presented herein are the results of a theoretical study of the static and dynamic hydroelastic instabilities of rigid supercavitating hydrofoils on elastic supports. A two-dimensional theory is used to define the unsteady hydrodynamic force and moment acting on the oscillating foil, which is assumed to be elastically restrained in translation normal to the free-stream direction and in rotation about a prescribed axis which is normal to the plane of flow. All other motions are neglected. The effects of variation in the elastic and inertial properties, as well as the effect of varying the position of the upper surface flow-separation point on the possibility of either form of instability, are determined. Also, the effect of cavitation number over a small range near zero is hypothesized. The theory predicts that dynamic instability (bending-torsion flutter) is possible at the density ratios typical of supercavitating operation. This is in contrast to the results for fully-wetted flow, where the occurrence of flutter is unlikely at the structural-to-fluid density ratios typical of hydrodynamic operation. The flutter possible in supercavitated operation is also more severe than that indicated for fully-wetted flow. Furthermore, it is shown that for the supercavitating hydrofoil, static instability (torsional divergence) and dynamic instability are of equal importance which again differs from the results in fully-wetted flow where static instability was shown to be the more important practical problem. Recommendations are made for experimental studies to verify these theoretical results.

Self-Aligning Hot-Wire Probe

1967 ◽  
Vol 71 (681) ◽  
pp. 657-658 ◽  
Author(s):  
A. D. Bond ◽  
A. M. Porter
Keyword(s):  
Constant Temperature ◽  
Two Dimensional ◽  
Servo Motor ◽  
Hot Wire ◽  
Turbulence Measurements ◽  
Wire Probe ◽  
Two Dimensional Flow ◽  
The Wire ◽  
Single Constant ◽  
Stream Direction

Summary:—This note describes how a single constant temperature hot wire may be used for measurements of direction, velocity and turbulence in a two-dimensional flow. The wire probe is rotated by a servo motor which automatically sets the wire with its axis either in the stream direction or normal to the flow. The accuracy of setting the wire in the direction of the stream is about , and across the stream is about 1°. If the higher accuracy is demanded the velocity and turbulence measurements require a second setting of the probe, at 90° to the previous one. When less precision is acceptable, the angle, velocity and turbulence measurements may be taken at the single setting, normal to the stream.

Vortex shedding from bluff bodies in a shear flow

1973 ◽  
Vol 60 (2) ◽  
pp. 401-409 ◽  
Author(s):  
D. J. Maull ◽  
R. A. Young
Keyword(s):  
Shear Flow ◽  
Vortex Shedding ◽  
Bluff Body ◽  
Pressure Coefficient ◽  
Uniform Flow ◽  
Base Pressure ◽  
Longitudinal Vortex ◽  
Bluff Bodies ◽  
Stream Direction

Experiments are described in which the vortex shedding from a bluff body and the base pressure coefficient have been measured in a shear flow. It is shown that the shedding breaks down into a number of spanwise cells in each of which the frequency is constant. The division between the cells is thought to be marked by a longitudinal vortex in the stream direction and this is supported by evidence from experiments where a longitudinal vortex was generated in an otherwise uniform flow.

On the dynamical relevance of coherent vortical structures in turbulent boundary layers

2010 ◽  
Vol 648 ◽  
pp. 325-349 ◽  
Author(s):  
SERGIO PIROZZOLI ◽  
MATTEO BERNARDINI ◽  
FRANCESCO GRASSO
Keyword(s):  
Viscous Sublayer ◽  
Momentum Balance ◽  
Substantial Contribution ◽  
Vortex Sheets ◽  
Vortical Structures ◽  
Buffer Region ◽  
Non Local ◽  
Low Speed Streaks ◽  
Vortex Tubes ◽  
Stream Direction

The dynamical relevance of vortex tubes and vortex sheets in a wall-bounded supersonic turbulent flow at Mach numberM= 2 and Reynolds numberReθ≈ 1350 is quantitatively analysed. The flow in the viscous sublayer and in the buffer region is characterized by intense, elongated vorticity tongues forming a shallow angle with respect to the wall, whose characteristic length isO(200) wall units and whose size in the cross-stream direction isO(50) wall units. The formation of vortex tubes takes place starting fromy+≈ 10, and it is mainly associated with the roll-up and the interaction of vortex sheets. The analysis of the non-local dynamical effect of tubes and sheets suggests that the latter have a more important collective effect, being closely associated with low-speed streaks, and being responsible for a substantial contribution to the mean momentum balance and to the production of turbulence kinetic energy and enstrophy.

Some Effects of Upstream Turbulence on the Unsteady Lift Forces Imposed on Prismatic Two Dimensional Bodies

1984 ◽  
Vol 106 (4) ◽  
pp. 418-424 ◽  
Author(s):  
I. S. Gartshore
Keyword(s):  
Small Scale ◽  
Resonant Amplitude ◽  
Scale Free ◽  
Free Stream Turbulence ◽  
Subsequent Decrease ◽  
Scale Turbulence ◽  
Oncoming Stream ◽  
Rms Amplitude ◽  
Stream Direction ◽  
Unsteady Lift

Measurements of fluctuating lift are reported from four fixed rectangular prisms and a fixed circular cylinder, for various intensities of turbulence in the oncoming stream. Variations of unsteady lift with intensity of small scale turbulence are similar to present (and previous) measured variations of mean drag or base pressure. Reasons are suggested for these trends. Observations are also reported of the maximum (resonant) RMS amplitude of two cylinders, one square and the other circular in cross section, free to move in the cross stream direction. Small scale free stream turbulence provided by the wake of a small upstream rod increased the resonant amplitude of motion in both cases, the greater increase (and subsequent decrease) occurring for the square section. Two possible explanations for these observations are advanced.

Transverse motion of an elastic sphere in a shear field

1973 ◽  
Vol 59 (1) ◽  
pp. 177-185 ◽  
Author(s):  
Christopher K. W. Tam ◽  
William A. Hyman
Keyword(s):  
Free Stream ◽  
Spherical Shape ◽  
Transverse Motion ◽  
Elastic Sphere ◽  
Shear Field ◽  
Elastic Particle ◽  
Small Deformations ◽  
Viscous Stresses ◽  
Stream Direction

The forces acting on an elastic particle suspended in a shear field, and moving relative to it, are found for the case in which there are small deformations from an initially spherical shape. The deformation is the result of the viscous stresses acting on the particle. Of principal interest is that there is a component of the force perpendicular to the free-stream direction, so that the particle will migrate across the undisturbed streamlines.

Sign in / Sign up

Export Citation Format

Share Document