One-dimensional simulation of Couette–Poiseuille flow with variable cross section for the full range of gas rarefaction

2020 ◽  
Vol 38 (4) ◽  
pp. 044201
Author(s):  
Timo Jünemann ◽  
Andreas Brümmer
Keyword(s):  
Cross Section ◽  
Poiseuille Flow ◽  
Full Range ◽  
Variable Cross Section ◽  
Variable Cross ◽  
One Dimensional ◽  
Dimensional Simulation

Stress Wave Propagation Analysis in One-Dimensional Micropolar Rods with Variable Cross-Section Using Micropolar Wave Finite Element Method

2018 ◽  
Vol 10 (04) ◽  
pp. 1850039 ◽  
Author(s):  
Mohsen Mirzajani ◽  
Naser Khaji ◽  
Muneo Hori
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Propagation ◽  
Cross Section ◽  
Variable Cross Section ◽  
Stress Wave Propagation ◽  
Rotational Degree ◽  
Variable Cross ◽  
One Dimensional ◽  
Element Method

The wave finite element method (WFEM) is developed to simulate the wave propagation in one-dimensional problem of nonhomogeneous linear micropolar rod of variable cross-section. For this purpose, two kinds of waves with fast and slow velocities are detected. For micropolar medium, an additional rotational degree of freedom (DOF) is considered besides the classical elasticity’s DOF. The proposed method is implemented to solve the wave propagation, reflection and transmission of two distinct waves and impact problems in micropolar rods with different layers. Along with new solutions, results of the micropolar wave finite element method (MWFEM) are compared with some numerical and/or analytical solutions available in the literature, which indicate excellent agreements between the results.

Approximate Calculation of Overdriven Gaseous Detonation in Convergent Channels

2011 ◽  
Vol 6 (2) ◽  
pp. 5-9
Author(s):  
Evgeniy S. Prokhorov
Keyword(s):  
Detonation Wave ◽  
Cross Section ◽  
Approximate Calculation ◽  
Detonation Front ◽  
Variable Cross Section ◽  
Gaseous Detonation ◽  
Variable Cross ◽  
Dimensional Model ◽  
Narrow Tube ◽  
One Dimensional

A simple quasi-one-dimensional model is presented to describe the propagation of gaseous detonation in a channel with variable cross-section. This model is applicable for the approximate analytical calculations of the degree overdrive of detonation wave in the transition of detonation from a broad to a narrow tube, and estimating the values of gasdynamic parameters at the detonation front

Adaptive Concepts for Herschel–Quincke Waveguides

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Jose S. Alonso ◽  
Ricardo A. Burdisso ◽  
Douglas Ivers ◽  
Hwa W. Kwan
Keyword(s):  
Frequency Shift ◽  
Cross Section ◽  
Frequency Tuning ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Noise Attenuation ◽  
Tonal Noise ◽  
Finite Area ◽  
One Dimensional ◽  
Adaptive Capabilities

The enhancement of Herschel–Quincke (HQ) waveguides to incorporate adaptive capabilities is investigated. Passive HQ waveguides are known to provide noise attenuation in pipes and ducts at selective narrow frequency bands associated with their resonances. The approach to achieve adaptation is to produce a frequency shift in these resonances to allow targeting incoming tonal noise of variable frequency. The frequency shift is obtained by placing a variable cross-section constriction along the interior of the waveguide. Two adaptive devices are considered. The first consists of a ball with fixed diameter that can be axially displaced inside the waveguide. Then, the frequency tuning is obtained as a function of the ball position. The second device consists of a diaphragm at fixed axial location which can be deformed to obtain a variable cross section. In this case, the frequency shift is obtained as a function of the diaphragm deflection. The internal acoustic dynamics of the two devices are investigated both analytically and experimentally. The created constriction inside the HQ waveguide is modeled as a series of constant cross-section tube elements with small finite area jump between adjacent pieces. The model is validated by comparing the predicted dynamics with experimental data from an extended impedance tube setup based on the two-microphone technique. Finally, attenuation predictions on a one-dimensional pipe are presented in order to illustrate the performance of the proposed adaptive HQ waveguides.

Investigation of the Impact of Sintering on SOFC Charge Transfer

2011 ◽  
Author(s):  
George J. Nelson ◽  
Brice N. Cassenti ◽  
Aldo A. Peracchio ◽  
Wilson K. S. Chiu
Keyword(s):  
Charge Transfer ◽  
Cross Section ◽  
Performance Metrics ◽  
Periodic Structures ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Two Dimensional ◽  
One Dimensional ◽  
Simplified Approach ◽  
The Impact

Solid oxide fuel cell electrodes are porous composites commonly produced by the sintering of powder compacts. Particle contact geometry within the electrode microstructure has been noted to impact electrode performance, particularly with respect to charge transfer. An analytical modeling concept has been applied to charge transport within the SOFC electrode microstructure using an approach similar to thermal fin analysis. This approach has the ability to account for variable cross-section solid geometry and replicates experimentally observed behavior related to SOFC electrode sintering quality. Microstructural geometries simulated by periodic structures composed of iterated base units with variable cross-section are investigated using two approaches: an axisymmetric one-dimensional analytical solution and an axisymmetric two-dimensional finite element solution. Results are cast in terms of dimensionless parameters and performance metrics that have been developed to assess the quality of SOFC electrode microstructures. Comparison of the one-dimensional and two-dimensional results demonstrates the predictive capabilities of the simplified approach.

Boundary element method in numerical study of three-dimensional Stokes flows in channels of arbitrary shape

2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Periodic Flows ◽  
Element Method

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.

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