Approximate models of one-dimensional pulsation of a cylindrical cavity in an incompressible fluid

1976 ◽  
Vol 12 (5) ◽  
pp. 687-691 ◽  
Author(s):  
V. K. Kedrinskii
Keyword(s):  
Incompressible Fluid ◽  
Cylindrical Cavity ◽  
One Dimensional ◽  
Approximate Models

Modeling of Shear Rheological Behavior of Uncured Rubber Melt

2020 ◽  
Vol 30 (1) ◽  
pp. 130-137
Author(s):  
Hengxiao Yang ◽  
Qimian Mo ◽  
Hengyu Lu ◽  
Shixun Zhang ◽  
Wei Cao ◽  
...  
Keyword(s):  
Shear Rate ◽  
Constitutive Model ◽  
Incompressible Fluid ◽  
Rheological Behavior ◽  
Rheological Characteristics ◽  
One Dimensional ◽  
Ptt Model ◽  
Rate Region ◽  
Proposed Model ◽  
Rheological Experiments

AbstractTo describe uncured rubber melt flow, a modified Phan–Thien–Tanner (PTT) model was proposed to characterize the rheological behavior and a viscoelastic one-dimensional flow theory was established in terms of incompressible fluid. The corresponding numerical method was constructed to determine the solution. Rotational rheological experiments were conducted to validate the proposed model. The influence of the parameters in the constitutive model was investigated by comparing the calculated and experimental viscosity to determine the most suitable parameters. The uncured rubber viscosity was 3–4 orders larger than that of plastic and did not have a visible Newtonian region. Compared with the Cross-Williams-Landel-Ferry (Cross-WLF) and original PTT models, the modified PTT model can describe the rheological characteristics in the entire shear-rate region if the parameters are set correctly.

Flow Through a Deformable Porous Material

1975 ◽  
Vol 42 (3) ◽  
pp. 598-602 ◽  
Author(s):  
G. S. Beavers ◽  
T. A. Wilson ◽  
B. A. Masha
Keyword(s):  
Porous Material ◽  
Incompressible Fluid ◽  
Applied Pressure ◽  
Local Stress ◽  
Darcy Law ◽  
Stress Dependence ◽  
One Dimensional ◽  
Flow Through ◽  
Incompressible Media ◽  
The One

A model is presented to describe the one-dimensional flow of an incompressible fluid through a deformable porous material. The model is based on the Forchheimer extension of the Darcy law for flows through incompressible media, where the Forchheimer coefficients are functions of the local stress. Experiments to determine the stress-dependence of the coefficients for polyurethane foam specimens are described. The coefficients are then used in the model to predict the mass flow rate through long polyurethane specimens as a function of the applied pressure difference across the material. The predictions of the model are compared with experimental observations.

scholarly journals Gravothermal Oscillations

1996 ◽  
Vol 174 ◽  
pp. 151-160 ◽  
Author(s):  
Junichiro Makino
Keyword(s):  
Temperature Inversion ◽  
Point Mass ◽  
Central Density ◽  
Expansion Phase ◽  
One Dimensional ◽  
Maximum Expansion ◽  
The Core ◽  
Approximate Models ◽  
Number Of Particles ◽  
Fokker Planck

We present the first clear evidence that the gravothermal oscillation takes place in N-body systems. We performed direct N-body simulations of systems of point-mass particles with particle numbers from 2,048 to 32,768. In the simulation with 32,768 particles, the central density shows an oscillation with an amplitude of ∼ 103, which is similar to what was observed in more approximate models such as a conducting gas sphere and one-dimensional Fokker-Planck calculations. The amplitude is smaller for a smaller number of particles. The number of particles in the core at the maximum contraction is ∼ 10 for all runs, while the number of particles at the maximum expansion is about 0.01N. For 16,384- and 32,768-body runs, the temperature inversion during the expansion phase is clearly visible.

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