scholarly journals Seismically constrained two-dimensional crustal thermal structure of the cambay basin

2001 ◽  
Vol 110 (1) ◽  
pp. 1-8 ◽  
Author(s):  
S. Thiagarajan ◽  
D. V. Ramana ◽  
S. N. Rai
Keyword(s):  
Thermal Structure ◽  
Two Dimensional ◽  
Cambay Basin ◽  
Crustal Thermal Structure

scholarly journals Two-dimensional modeling of density and thermal structure of dense circumstellar outflowing disks

2018 ◽  
Vol 613 ◽  
pp. A75 ◽  
Author(s):  
P. Kurfürst ◽  
A. Feldmeier ◽  
J. Krtička
Keyword(s):  
Mass Loss ◽  
Optical Depth ◽  
Massive Stars ◽  
Thermal Structure ◽  
Time Dependent ◽  
Navier Stokes ◽  
Viscous Heating ◽  
Two Dimensional ◽  
Dense Region ◽  
Loss Rates

Context. Evolution of massive stars is affected by a significant loss of mass either via (nearly) spherically symmetric stellar winds or by aspherical mass-loss mechanisms, namely the outflowing equatorial disks. However, the scenario that leads to the formation of a disk or rings of gas and dust around massive stars is still under debate. It is also unclear how various forming physical mechanisms of the circumstellar environment affect its shape and density, as well as its kinematic and thermal structure. Aims. We study the hydrodynamic and thermal structure of optically thick, dense parts of outflowing circumstellar disks that may be formed around various types of critically rotating massive stars, for example, Be stars, B[e] supergiant (sgB[e]) stars or Pop III stars. We calculate self-consistent time-dependent models of temperature and density structure in the disk’s inner dense region that is strongly affected by irradiation from a rotationally oblate central star and by viscous heating. Methods. Using the method of short characteristics, we specify the optical depth of the disk along the line-of-sight from stellar poles. Within the optically thick dense region with an optical depth of τ > 2∕3 we calculate the vertical disk thermal structure using the diffusion approximation while for the optically thin outer layers we assume a local thermodynamic equilibrium with the impinging stellar irradiation. For time-dependent hydrodynamic modeling, we use two of our own types of hydrodynamic codes: two-dimensional operator-split numerical code based on an explicit Eulerian finite volume scheme on a staggered grid, and unsplit code based on the Roe’s method, both including full second-order Navier-Stokes shear viscosity. Results. Our models show the geometric distribution and contribution of viscous heating that begins to dominate in the central part of the disk for mass-loss rates higher than Ṁ ≳ 10−10 M⊙ yr−1. In the models of dense viscous disks with Ṁ > 10−8 M⊙ yr−1, the viscosity increases the central temperature up to several tens of thousands of Kelvins, however the temperature rapidly drops with radius and with distance from the disk midplane. The high mass-loss rates and high viscosity lead to instabilities with significant waves or bumps in density and temperature in the very inner disk region. Conclusions. The two-dimensional radial-vertical models of dense outflowing disks including the full Navier-Stokes viscosity terms show very high temperatures that are however limited to only the central disk cores inside the optically thick area, while near the edge of the optically thick region the temperature may be low enough for the existence of neutral hydrogen, for example.

Application of a two-dimensional hydrodynamic reservoir model to Lake Erie

2001 ◽  
Vol 58 (5) ◽  
pp. 858-869 ◽  
Author(s):  
L Boegman ◽  
M R Loewen ◽  
P F Hamblin ◽  
D A Culver
Keyword(s):  
Lake Erie ◽  
Nutrient Loading ◽  
Thermal Structure ◽  
Domain Model ◽  
Water Level Fluctuations ◽  
Two Dimensional ◽  
Large Lakes ◽  
Physical Forcing ◽  
Model Predictions ◽  
Averaged Model

The relative impacts of changes in nutrient loading and zebra mussel establishment on plankton in large lakes are strongly influenced by hydrodynamics, yet adequately modelling the temporal-spatial complexity of physical and biological processes has been difficult. We adapted a two-dimensional public domain model, CE-QUAL-W2, to test whether it could provide a hydrodynamically accurate simulation of the seasonal variation in the vertical-longitudinal thermal structure of Lake Erie. The physical forcing for the model is derived from surface meteorological buoys and measurements of precipitation, inflows, and outflows. To calibrate and validate the model, predictions were compared with an extensive set of field data collected during May through September 1994. The model accurately predicted water-level fluctuations without adjustment. However, significant modifications to the eddy coefficient turbulence algorithm were required to simulate acceptable longitudinal currents. The thermal structure was accurately predicted in all three basins, even though this laterally averaged model cannot simulate Coriolis effects. We are currently extending the model's water-quality module to include the effects of nutrient loading and zebra mussels on the plankton.

Terrestrial heat flow and crustal thermal structure in the northern slope of Tazhong uplift in Tarim Basin

Geothermics ◽  
2020 ◽  
Vol 83 ◽  
pp. 101709
Author(s):  
Yuchen Liu ◽  
Nansheng Qiu ◽  
Huili Li ◽  
Anlai Ma ◽  
Jian Chang ◽  
...  
Keyword(s):  
Heat Flow ◽  
Tarim Basin ◽  
Thermal Structure ◽  
Northern Slope ◽  
Terrestrial Heat Flow ◽  
Crustal Thermal Structure ◽  
Tazhong Uplift

Terrestrial heat flow and crustal thermal structure of the Gonghe-Guide area, northeastern Qinghai-Tibetan plateau

Geothermics ◽  
2018 ◽  
Vol 72 ◽  
pp. 182-192 ◽  
Author(s):  
Chao Zhang ◽  
Guangzheng Jiang ◽  
Yizuo Shi ◽  
Zhuting Wang ◽  
Yi Wang ◽  
...  
Keyword(s):  
Heat Flow ◽  
Tibetan Plateau ◽  
Thermal Structure ◽  
Terrestrial Heat Flow ◽  
Crustal Thermal Structure
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