Turbulence as a Producer of Noise in Proportional Fluid Amplifiers

1966 ◽  
Vol 33 (4) ◽  
pp. 728-734
Author(s):  
D. W. Prosser ◽  
M. J. Fisher
Keyword(s):  
Experimental Verification ◽  
Momentum Flux ◽  
Turbulent Jet ◽  
Two Dimensional ◽  
Relative Movement ◽  
Signal Ratio ◽  
Flow Through

A theory was developed to predict the signal and noise, in terms of stagnation pressures, at the entrance to a blocked rectangular receiver placed in an otherwise free two-dimensional turbulent jet. Experimental verification of the theory was then undertaken. The results showed that a reversal of flow takes place within the entrance of a blocked receiver, so that stagnation conditions do not exist at the entrance and, hence, the theory is not valid under these conditions. The theory was easily altered to predict the momentum flux through a receiver which presents very little resistance to flow through its passageway. Employing a device called a momentum meter the altered theory was verified. The main results of this work are: (a) The noise-to-signal ratio of a receiver held fixed in the jet is minimized by keeping the receiver near the centerline of the jet. (b) The ratio of noise to change in signal, with relative movement between the jet and receiver, is minimized by keeping the receiver away from the centerline of the power jet.

Two-Dimensional Flow With Standing Vortexes in Ducts and Diffusers

1960 ◽  
Vol 82 (4) ◽  
pp. 921-927 ◽  
Author(s):  
Friedrich O. Ringleb
Keyword(s):  
Wind Tunnel ◽  
Potential Flow ◽  
Separation Control ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Princeton University ◽  
Two Dimensional Flow ◽  
Flow Through ◽  
Trapping Devices

The conditions for the equilibrium of two vortexes in a two-dimensional flow through a duct or diffuser are derived. Potential-flow considerations and a few basic results from viscous-flow theory are used for the discussion of the role of cusps as separation control and trapping devices for standing vortexes. The investigations are applied to cusp diffusers especially with regard to the wind tunnel of the James Forrestal Research Center of Princeton University.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

scholarly journals The Turbulent Jet from a Series of Holes in Line

1964 ◽  
Vol 15 (1) ◽  
pp. 1-28 ◽  
Author(s):  
R. Knystautas
Keyword(s):  
Jet Flow ◽  
Turbulent Jet ◽  
Two Dimensional ◽  
Turbulent Jet Flow ◽  
Similar Density

SummaryThe possibility of obtaining two-dimensional turbulent jet flow from a series of closely-spaced uniform holes in line has been investigated both theoretically and experimentally. The case studied was that of a jet discharging into still fluid of similar density at incompressible speeds. Such a quasi-two-dimensional jet is a particular example of a multiple-interfering jet group.

Laminar flow in symmetrical channels with slightly curved walls II. An asymptotic series for the stream function

1963 ◽  
Vol 272 (1350) ◽  
pp. 406-428 ◽  
Keyword(s):  
Laminar Flow ◽  
Asymptotic Series ◽  
Radius Of Curvature ◽  
Two Dimensional ◽  
The Third ◽  
Higher Order Terms ◽  
Curvature Parameter ◽  
Leading Term ◽  
Flow Through ◽  
Curved Walls

A class of two-dimensional channels, with walls whose radius of curvature is uniformly large relative to local channel width, is described, and the velocity field of laminar flow through these channels is obtained as a power series in the small curvature parameter. The leading term is the Jeffery-Hamel solution considered in part I, and it is shown here how the higher-order terms are found. Terms of the third approximation have been computed. The theory is applied to two examples, for one of which experimental results are available and confirm the theoretical values with fair accuracy.

Flow Fields in a Two-Dimensional Diffuser With Extraction of Fluid on the Diverging Walls

1972 ◽  
Vol 94 (3) ◽  
pp. 226-232
Author(s):  
D. O. Rockwell
Keyword(s):  
Experimental Verification ◽  
Static Pressure ◽  
Flow Fields ◽  
Hydrogen Bubble ◽  
Two Dimensional ◽  
Stagnation Region ◽  
Pressure Distributions

A theory is developed to describe the inviscid core in two-dimensional unstalled diffusers with suction (extraction) on the diverging walls. Experimental wall static pressure distributions and streamline patterns agree well with those predicted theoretically. Under appropriate extraction conditions, a stagnation region is located downstream of the diverging wall extraction station. Experimental verification of the streamline patterns and of the location of this stagnation region was achieved via hydrogen bubble visualization. In addition, the possible stall conditions, which result if improper extraction is employed, are described qualitatively.

scholarly journals Analysis of base characteristics of trench gate field termination IGBT

2021 ◽  
Vol 237 ◽  
pp. 02023
Author(s):  
Bo Wang
Keyword(s):  
Coordinate System ◽  
Experimental Verification ◽  
Carrier Transport ◽  
Model Analysis ◽  
Bipolar Transistor ◽  
Two Dimensional ◽  
Base Region ◽  
Dimensional Effect ◽  
Insulated Gate Bipolar Transistor ◽  
Gate Structure

Trench gate structure represents the latest structure of Insulated Gate Bipolar Transistor(IGBT). Because there are great differences in model analysis coordinate system and carrier transport between trench gate structure and planar gate structure, the modeling method using planar gate structure will inevitably have great deviation. Based on the characteristics of trench gate structure and model analysis coordinate system, the base region is divided into PNP and PIN by considering the two-dimensional effect of carriers. According to whether the trench of PIN part can be covered by depletion layer of PNP part, the specific base region current is analyzed. Finally, simulation and experimental verification are carried out.

scholarly journals Numerical Analysis of Fluid Flow on Wall Cylinder Circular with K-ε Modeling for a High Reynolds Rate

2019 ◽  
Vol 1 (3) ◽  
pp. 43-50
Author(s):  
M. Yasep Setiawan ◽  
Wawan Purwanto ◽  
Wanda Afnison ◽  
Nuzul Hidayat
Keyword(s):  
Fluid Flow ◽  
Numerical Study ◽  
General Procedure ◽  
Circular Cylinders ◽  
Cylinder Wall ◽  
Two Dimensional ◽  
Third Order ◽  
Physical Information ◽  
Flow Through ◽  
High Reynolds

This study discusses the numerical study of two-dimensional analysis of flow through circular cylinders. The original physical information entered in the equation governing most of the modeling is transferred into a numerical solution. Fluid flow on two-dimensional circular cylinder wall using high Reynolds k-ε modeling (Re = 106), Here we will do 3 modeling first oder upwind, second order upwind and third order MUSCL by using k-ε standard.  The general procedure for this research is formulated in detail for allocations in the dynamic analysis of fluid computing. The results of this study suggest that MUSCL's third order modeling gives more accurate results better than other models.

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