scholarly journals Collapse of a Relativistic Self-Gravitating Star with Radial Heat Flux: Impact of Anisotropic Stresses

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ranjan Sharma ◽  
Shyam Das

We develop a simple model for a self-gravitating spherically symmetric relativistic star which begins to collapse from an initially static configuration by dissipating energy in the form of radial heat flow. We utilize the model to show how local anisotropy affects the collapse rate and thermal behavior of gravitationally evolving systems.

2021 ◽  
Vol 13 (1) ◽  
pp. 54-59
Author(s):  
Andriy Ilchenko ◽  

The article analyzes the influence, relationship and value of design parameters of the heat flow meter on its radial and axial heat fluxes in the tube (tube diameter, heater diameter and their ratio, thermal conductivity of the tube material, etc.). It is shown that at the stage of choosing the design parameters of the flowmeter it is necessary to take into account the influence of its radial heat flux on the axial one. The influence of radial heat flux in the flowmeter tube on the error of fuel loss measurement is substantiated. Analytical dependences which allow to define an axial heat stream are resulted, their analysis concerning influence of flowmeter tube constructive parameters on heat transfer is carried out. Measures are planned and recommendations are developed for the choice of design flowmeter parameters, development or use, provided that the influence of radial heat flow on the axial is reduced, which will reduce the total error of fuel consumption measurement. Regarding the choice of design parameters of heat meters while reducing the error of measuring fuel consumption, it is shown that the maximum possible decrease in the diameter of the heater and increase the diameter of the flow tube reduce the impact of radial heat flow on the axial and thus reduce the total fuel consumption error. Numerical ratios of tube diameter to flowmeter heater diameter for different thermal conductivities of tube materials are given under the condition of minimal influence on fuel consumption measurement error. For tube materials with a thermal conductivity 0.16… 0.25 W / (m ∙ K) (ebonite, fluoroplastic F-5, etc.) the tube diameters ratio and the heater should be within 1.51… 1.62, and for materials with more high thermal conductivity (thermal conductivity greater than 14.9 W / (m ∙ K)), this ratio should be equal to 1.99.


2003 ◽  
Vol 12 (04) ◽  
pp. 667-676 ◽  
Author(s):  
M. GOVENDER ◽  
K. S. GOVINDER ◽  
S. D. MAHARAJ ◽  
R. SHARMA ◽  
S. MUKHERJEE ◽  
...  

We present here a simple model of radiative gravitational collapse with radial heat flux which describes qualitatively the stages close to the formation of a superdense cold star. Starting with a static general solution for a cold star, the model can generate solutions for the earlier evolutionary stages. The temporal evolution of the model is specified by solving the junction conditions appropriate for radiating gravitational collapse. The results will be useful in constructing models for the evolution of X-ray pulsars, like Her X-1.


2013 ◽  
Vol 22 (07) ◽  
pp. 1350049 ◽  
Author(s):  
M. GOVENDER

In this paper, we present an exact model of a spherically symmetric star undergoing dissipative collapse in the form of a radial heat flux. The interior of the star is matched smoothly to the generalized Vaidya line element representing a two-fluid atmosphere comprising null radiation and a string fluid. The influence of the string density on the thermal behavior of the model is investigated by employing a causal heat transport equation of Maxwell–Cattaneo form.


2021 ◽  
Vol 172 ◽  
pp. 112854
Author(s):  
Maulik Panchal ◽  
Vrushabh Lambade ◽  
Vimal Kanpariya ◽  
Harsh Patel ◽  
Paritosh Chaudhuri

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