“Maximum” entropy production in self-organized plasma boundary layer: A thermodynamic discussion about turbulent heat transport

2008 ◽  
Vol 15 (3) ◽  
pp. 032307 ◽  
Author(s):  
Z. Yoshida ◽  
S. M. Mahajan
Keyword(s):  
Boundary Layer ◽  
Entropy Production ◽  
Maximum Entropy ◽  
Heat Transport ◽  
Plasma Boundary ◽  
Turbulent Heat ◽  
Maximum Entropy Production ◽  
Self Organized

scholarly journals Maximum entropy production allows a simple representation of heterogeneity in semiarid ecosystems

2010 ◽  
Vol 365 (1545) ◽  
pp. 1449-1455 ◽  
Author(s):  
Stanislaus J. Schymanski ◽  
Axel Kleidon ◽  
Marc Stieglitz ◽  
Jatin Narula
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Bare Soil ◽  
Vegetation Patterns ◽  
Subgrid Scale ◽  
Infiltration Capacity ◽  
Semiarid Ecosystems ◽  
Maximum Entropy Production ◽  
Self Organized ◽  
Scale Heterogeneity

Feedbacks between water use, biomass and infiltration capacity in semiarid ecosystems have been shown to lead to the spontaneous formation of vegetation patterns in a simple model. The formation of patterns permits the maintenance of larger overall biomass at low rainfall rates compared with homogeneous vegetation. This results in a bias of models run at larger scales neglecting subgrid-scale variability. In the present study, we investigate the question whether subgrid-scale heterogeneity can be parameterized as the outcome of optimal partitioning between bare soil and vegetated area. We find that a two-box model reproduces the time-averaged biomass of the patterns emerging in a 100 × 100 grid model if the vegetated fraction is optimized for maximum entropy production (MEP). This suggests that the proposed optimality-based representation of subgrid-scale heterogeneity may be generally applicable to different systems and at different scales. The implications for our understanding of self-organized behaviour and its modelling are discussed.

scholarly journals The Atmospheric Response to Surface Heating under Maximum Entropy Production

2014 ◽  
Vol 71 (6) ◽  
pp. 2204-2220
Author(s):  
A. Gjermundsen ◽  
J. H. LaCasce ◽  
L. S. Graff
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Heat Transport ◽  
General Circulation ◽  
Heat Fluxes ◽  
Storm Tracks ◽  
Atmospheric Response ◽  
Maximum Entropy Production ◽  
Surface Temperatures ◽  
Low Latitudes

Abstract In numerous studies, midlatitude storm tracks have been shown to shift poleward under global warming scenarios. Among the possible causes, changes in sea surface temperature (SST) have been shown to affect both the intensity and the position of the tracks. Increased SSTs can increase both the lateral heating occurring in the tropics and the midlatitude temperature gradients, both of which increase tropospheric baroclinicity. To better understand the response to altered SST, a simplified energy balance model (EBM) is used. This employs the principal of maximum entropy production (MEP) to determine the meridional heat fluxes in the atmosphere. The model is similar to one proposed by Paltridge (1975) but represents only the atmospheric response (the surface temperatures are fixed). The model is then compared with a full atmospheric general circulation model [Community Atmosphere Model, version 3 (CAM3)]. In response to perturbed surface temperatures, EBM exhibits similar changes in (vertically integrated) air temperature, convective heat fluxes, and meridional heat transport. However, the changes in CAM3 are often more localized, particularly at low latitudes. This, in turn, results in a shift of the storm tracks in CAM3, which is largely absent in EBM. EBM is more successful, however, at representing the response to changes in high-latitude heating or cooling. Therefore, MEP is evidently a plausible representation for heat transport in the midlatitudes, but not necessarily at low latitudes.

scholarly journals Vertical and horizontal processes in the global atmosphere and the maximum entropy production conjecture

2012 ◽  
Vol 3 (1) ◽  
pp. 19-32 ◽  
Author(s):  
S. Pascale ◽  
J. M. Gregory ◽  
M. H. P. Ambaum ◽  
R. Tailleux ◽  
V. Lucarini
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Heat Transport ◽  
Large Scale ◽  
Vertical Structure ◽  
Magnitude Estimate ◽  
Heat Fluxes ◽  
Box Model ◽  
Maximum Entropy Production ◽  
Vertical Heat

Abstract. The objective of this paper is to reconsider the Maximum Entropy Production conjecture (MEP) in the context of a very simple two-dimensional zonal-vertical climate model able to represent the total material entropy production due at the same time to both horizontal and vertical heat fluxes. MEP is applied first to a simple four-box model of climate which accounts for both horizontal and vertical material heat fluxes. It is shown that, under condition of fixed insolation, a MEP solution is found with reasonably realistic temperature and heat fluxes, thus generalising results from independent two-box horizontal or vertical models. It is also shown that the meridional and the vertical entropy production terms are independently involved in the maximisation and thus MEP can be applied to each subsystem with fixed boundary conditions. We then extend the four-box model by increasing its resolution, and compare it with GCM output. A MEP solution is found which is fairly realistic as far as the horizontal large scale organisation of the climate is concerned whereas the vertical structure looks to be unrealistic and presents seriously unstable features. This study suggest that the thermal meridional structure of the atmosphere is predicted fairly well by MEP once the insolation is given but the vertical structure of the atmosphere cannot be predicted satisfactorily by MEP unless constraints are imposed to represent the determination of longwave absorption by water vapour and clouds as a function of the state of the climate. Furthermore an order-of-magnitude estimate of contributions to the material entropy production due to horizontal and vertical processes within the climate system is provided by using two different methods. In both cases we found that approximately 40 mW m−2 K−1 of material entropy production is due to vertical heat transport and 5–7 mW m−2 K−1 to horizontal heat transport.

The mechanics of granitoid systems and maximum entropy production rates

2010 ◽  
Vol 368 (1910) ◽  
pp. 53-93 ◽  
Author(s):  
Bruce E. Hobbs ◽  
Alison Ord
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Melt Inclusions ◽  
Selection Process ◽  
Finite Thickness ◽  
Control Valve ◽  
Entropy Production Rate ◽  
Constitutive Behaviour ◽  
Maximum Entropy Production ◽  
Physical Height

A model for the formation of granitoid systems is developed involving melt production spatially below a rising isotherm that defines melt initiation. Production of the melt volumes necessary to form granitoid complexes within 10 4 –10 7 years demands control of the isotherm velocity by melt advection. This velocity is one control on the melt flux generated spatially just above the melt isotherm, which is the control valve for the behaviour of the complete granitoid system. Melt transport occurs in conduits initiated as sheets or tubes comprising melt inclusions arising from Gurson–Tvergaard constitutive behaviour. Such conduits appear as leucosomes parallel to lineations and foliations, and ductile and brittle dykes. The melt flux generated at the melt isotherm controls the position of the melt solidus isotherm and hence the physical height of the Transport/Emplacement Zone. A conduit width-selection process, driven by changes in melt viscosity and constitutive behaviour, operates within the Transport Zone to progressively increase the width of apertures upwards. Melt can also be driven horizontally by gradients in topography; these horizontal fluxes can be similar in magnitude to vertical fluxes. Fluxes induced by deformation can compete with both buoyancy and topographic-driven flow over all length scales and results locally in transient ‘ponds’ of melt. Pluton emplacement is controlled by the transition in constitutive behaviour of the melt/magma from elastic–viscous at high temperatures to elastic–plastic–viscous approaching the melt solidus enabling finite thickness plutons to develop. The system involves coupled feedback processes that grow at the expense of heat supplied to the system and compete with melt advection. The result is that limits are placed on the size and time scale of the system. Optimal characteristics of the system coincide with a state of maximum entropy production rate.

scholarly journals Relaxation Processes and the Maximum Entropy Production Principle

Entropy ◽  
2010 ◽  
Vol 12 (3) ◽  
pp. 473-479 ◽  
Author(s):  
Paško Županović ◽  
Srećko Botrić ◽  
Davor Juretić ◽  
Domagoj Kuić
Keyword(s):  
Entropy Production ◽  
Maximum Entropy ◽  
Relaxation Processes ◽  
Maximum Entropy Production
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