Multi‐control‐volume analysis of elastic and plastic wave fronts in composite materials

Previous studies have extended Benjamin's theory for an inertial steady-state gravity current of density $\rho _{c}$ in a homogeneous ambient fluid of density $\rho _{o} < \rho _{c}$ to the counterpart propagation in a linearly stratified (Boussinesq) ambient (density decreases from $\rho _b$ to $\rho _{o}$ ). The extension is typified by the parameter $S = (\rho _{b}-\rho _{o})/(\rho _{c}-\rho _{o}) \in (0,1]$ , uses Long's solution for the flow over a topography to model the flow of the ambient over the gravity current, and reduces well to the classical theory for small and moderate values of $S$ . However, for $S=1$ , i.e. $\rho _b = \rho _c$ , which corresponds to a symmetric intrusion, various idiosyncrasies appear. Here attention is focused on this case. The control-volume analysis (balance of volume, mass, momentum and vorticity) produces a fairly compact analytical formulation, pending a closure for the head loss, and subject to stability criteria (no inverse stratification downstream). However, we show that plausible closures that work well for the non-stratified current (like zero head loss on the stagnation line, or zero vorticity diffusion) do not produce satisfactory results for the intrusion (except for some small ranges of the height ratio of current to channel, $a = h/H$ ). The reasons and insights are discussed. Accurate data needed for comparison with the theoretical model are scarce, and a message of this paper is that dedicated experiments and simulations are needed for the clarification and improvement of the theory.

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Magnetic resonance velocity imaging derived pressure differential using control volume analysis

Fluids and Barriers of the CNS ◽

10.1186/2045-8118-8-16 ◽

2011 ◽

Vol 8 (1) ◽

pp. 16

Author(s):

Benjamin Cohen ◽

Abram Voorhees ◽

Timothy Wei

Keyword(s):

Magnetic Resonance ◽

Control Volume ◽

Pressure Differential ◽

Volume Analysis ◽

Velocity Imaging

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Injection Pump Analysis

Volume 2: Applied Fluid Mechanics; Electromechanical Systems and Mechatronics; Advanced Energy Systems; Thermal Engineering; Human Factors and Cognitive Engineering ◽

10.1115/esda2012-82093 ◽

2012 ◽

Author(s):

William W. Schultz ◽

Eric Johnsen ◽

Bosuk Han ◽

Sung Park

Keyword(s):

Control Volume ◽

Optimal Performance ◽

Device Performance ◽

Volume Analysis ◽

Injection Pump ◽

Simple Geometry ◽

Simplified Analysis ◽

Moving Parts

An injection pump is one of the simplest mechanics devices imaginable with no moving parts and a very simple geometry. We examine the device performance for steam injectors using primarily a control volume analysis and consider to what extent this simplified analysis represents optimal performance. We seek the rationale for performing CFD studies and develop optimization scenarios.

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Lift force for cylindrical and elliptical Coandă aircraft design

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.13.21345 ◽

2018 ◽

Vol 7 (4.13) ◽

pp. 137

Author(s):

Mohd Faisal Abdul Hamid ◽

Azmin Shakrine Mohd Rafie ◽

Ezanee Gires ◽

Abd. Rahim Abu Talib

Keyword(s):

Lift Force ◽

Control Volume ◽

Aircraft Design ◽

The Body ◽

Viscous Effect ◽

Extended Version ◽

Volume Analysis ◽

Flow Effects ◽

And Performance ◽

Rotary Wing

Small aerial vehicles possess advantages in terms of size and accessibility in performing a variety of tasks. Presently, their design and performance is dependent on variations of conventional aerodynamic configurations (fixed- and rotary-wing). A disadvantage for these configurations is the aerodynamic potential between the mainstream airflow and the body surfaces are not fully utilized. To solve this issue, the Coandă effect is proposed whereby a high-velocity jet is blown tangentially over a curved surface to increase circulation and lift. Prior to the costly approach (experimental and numerical), an analytical formulation (via control volume analysis) to predict the aerodynamic Coandă lift force of the design concept is developed. This is an extended version of the existing mathematical formulations, capturing viscous flow effects. It is also pertinent for circular and elliptical-shaped designs. The results obtained show that the total lift force is dependent on the jet velocity, outflow angle, dimensions of the jet slot, the projected surface area, and the viscous effect. The approach has demonstrated how this modelling technique is effective in calculating the lift force for cylindrical and elliptical Coandă aircraft design.

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Aerodynamic Throttling of Two-Dimensional Nozzle Flows

Aeronautical Quarterly ◽

10.1017/s0001925900006314 ◽

1972 ◽

Vol 23 (1) ◽

pp. 53-61 ◽

Cited By ~ 3

Author(s):

R H Nunn ◽

H Brandt

Keyword(s):

Control Volume ◽

Interaction Region ◽

Experimental Measurements ◽

Two Dimensional ◽

Volume Analysis ◽

Throat Region ◽

Mainstream Flow ◽

Nozzle Flows

SummaryThe inviscid interaction resulting from the penetration of a jet of air into the throat region of a bounded mainstream flow is investigated analytically and experimentally. Taking into account the effects of jet shocks, a control volume analysis is used to calculate the mainstream and jet conditions at the boundaries of the interaction region. These results are then used to estimate the shape of the interface separating the jet and mainstream. Particular attention is given to the throttling of the mainstream flow and the analytical predictions show agreement with the experimental measurements.

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Superconductive Property and Microstructure of MgB2 Particle-Dispersed Aluminum Based Composite Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.2759 ◽

2010 ◽

Vol 654-656 ◽

pp. 2759-2762

Author(s):

Manabu Mizutani ◽

Kenji Matsuda ◽

Kazuya Makino ◽

Katsuhiko Nishimura ◽

Tokimasa Kawabata ◽

...

Keyword(s):

Composite Materials ◽

Control Volume ◽

Superconducting Magnets ◽

Three Dimensional ◽

Original Method ◽

Superconducting Transition ◽

Superconducting Wires ◽

Al Composite ◽

The Matrix ◽

And Control

Superconducting wires have been applied for the fabrication of superconducting magnets in nuclear magneto-resonance (NMR), Magneto-resonance imaging (MRI) and so on. MgB2 has the highest critical temperature of superconducting transition (TC39K) among intermetallic compound superconductive materials. This means that MgB2 Superconductive wire doesn’t need expensive liquid He for cooling. We used the original method of the three-dimensional penetration casting (3DPC) in this laboratory to fabricate the MgB2/Al composite. Our 3DPC method for fabricating composite materials can disperse particles in the matrix homogenously without any aggregation and control volume fractions of composites within the range of 4 – 40%, even when particle size is less than 1 m. Thus, these composite materials can be processed by machining, extrusion and rolling. In the composite material we made, MgB2 particles dispersed to the Al matrix uniformly. The TC was determined by electrical resistivity and magnetization to be about 37 – 39K. We succeeded in extruding MgB2/Al composite billet to 1mm wire. Microstructures of these samples have been confirmed by SEM method. MgB2/Al composite billet and extruded wire were showed there no cracks inside the materials.

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