scholarly journals Mechanics and thermodynamics of a new minimal model of the atmosphere

2020 ◽  
Vol 135 (10) ◽  
Author(s):  
Gabriele Vissio ◽  
Valerio Lucarini
Keyword(s):  
Numerical Models ◽  
Preliminary Evidence ◽  
Chaotic Motions ◽  
One Dimensional ◽  
Fundamental Properties ◽  
Multiscale Dynamics ◽  
Energy Cycle ◽  
The One ◽  
Lorenz 96 ◽  
Model Features

AbstractThe understanding of the fundamental properties of the climate system has long benefitted from the use of simple numerical models able to parsimoniously represent the essential ingredients of its processes. Here, we introduce a new model for the atmosphere that is constructed by supplementing the now-classic Lorenz ’96 one-dimensional lattice model with temperature-like variables. The model features an energy cycle that allows for energy to be converted between the kinetic form and the potential form and for introducing a notion of efficiency. The model’s evolution is controlled by two contributions—a quasi-symplectic and a gradient one, which resemble (yet not conforming to) a metriplectic structure. After investigating the linear stability of the symmetric fixed point, we perform a systematic parametric investigation that allows us to define regions in the parameters space where at steady-state stationary, quasi-periodic, and chaotic motions are realised, and study how the terms responsible for defining the energy budget of the system depend on the external forcing injecting energy in the kinetic and in the potential energy reservoirs. Finally, we find preliminary evidence that the model features extensive chaos. We also introduce a more complex version of the model that is able to accommodate for multiscale dynamics and that features an energy cycle that more closely mimics the one of the Earth’s atmosphere.

Drying Rate of Wood Particles With Longitudinal Mass Transfer

1985 ◽  
Vol 107 (1) ◽  
pp. 12-18 ◽  
Author(s):  
B. Dorri ◽  
A. F. Emery ◽  
P. C. Malte
Keyword(s):  
Numerical Models ◽  
Spherical Particles ◽  
Drying Rate ◽  
Evaporation Front ◽  
Dimensional Model ◽  
One Dimensional ◽  
Wood Particles ◽  
Small Wood ◽  
The One ◽  
Rectangular Model

The drying of small wood particles of shape L:W:t = 3 to 5:2:1 is examined by three numerical models, and results are compared to measurements. (i) A one-dimensional rectangular model has liquid water concentrated in the center of a particle, and this is removed as an evaporation front propagates into the liquid. (ii) The one-dimensional model is also treated by the volume-averaged, or “smeared” approach, for which the moisture at any point is a distribution of liquid and vapor. For the simple rectangular geometry, the frontal and smeared models give similar results. (iii) Equivalent spherical particles are analyzed by a smeared model which includes capillarity. Reasonable agreement is obtained between the spherical results and the measurements, though an overprediction in drying rate occurs for slender particles.

scholarly journals A New Diffusion Scheme for Numerical Models Based on Full Irreversibility

2009 ◽  
Vol 24 (2) ◽  
pp. 595-600 ◽  
Author(s):  
C. Liu ◽  
Y. Liu ◽  
H. Xu
Keyword(s):  
Numerical Models ◽  
Weather Prediction ◽  
Forecast Accuracy ◽  
Second Law Of Thermodynamics ◽  
New Physics ◽  
Numerical Weather Prediction Model ◽  
One Dimensional ◽  
Diffusion Scheme ◽  
The One ◽  
Mean Square Errors

Abstract In this work, the forecast accuracy of a numerical weather prediction model is improved by emulating physical dissipation as suggested by the second law of thermodynamics, which controls the irreversible evolutionary direction of a many-body system like the atmosphere. The ability of the new physics-based scheme to improve model accuracy is demonstrated via the case of the one-dimensional viscous Burgers equation and the one-dimensional diffusion equation, as well as a series of numerical simulations of the well-known 1998 successive torrential rains along the Yangtze River valley and 365 continuous 24-h simulations during 2005–06 with decreased root-mean-square errors and improved forecasts in all of the simulations.

Local Blockage Effects for Idealised Turbines in Tidal Channels

2019 ◽  
Author(s):  
Lei Chen ◽  
Paul A. J. Bonar ◽  
Christopher R. Vogel ◽  
Thomas A. A. Adcock
Keyword(s):  
Oscillatory Flow ◽  
Numerical Models ◽  
Numerical Results ◽  
Tidal Channels ◽  
One Dimensional ◽  
Scale Theory ◽  
Actuator Disc ◽  
Tidal Turbine ◽  
The One ◽  
Turbine Arrays

Abstract In this paper, idealised analytical and numerical models are used to explore the potential for local blockage effects to enhance the performance of turbines in tidal channels. Arrays of turbines modelled using the volume-flux-constrained actuator disc and blade element momentum theories are embedded within one-dimensional analytical and two-dimensional numerical channel domains. The effects of local blockage on the performance of arrays comprising one and five rows of actuator discs and tidal rotors operating in steady and oscillatory channel flow are then examined. In the case of steady flow, numerical results are found to agree very well with the two-scale actuator disc theory of Nishino & Willden [1]. In the case of oscillatory flow, however, numerical results show that the shorter and more highly blocked arrays produce considerably more power than predicted by the one-dimensional two-scale theory. These results support the findings of Bonar et al. [2], who showed that under certain oscillatory flow conditions, the power produced by a partial-width tidal turbine array can be much greater than predicted by two-scale theory. The departure from theory is most noticeable in the case of five turbine rows, where the two-scale theory predicts that the maximum available power should decrease with increasing local blockage but the numerical model shows the maximum available power to increase. The effects of local blockage are found to be less pronounced for the more realistic tidal rotor than for the highly idealised actuator disc but for both models, the results show that in oscillatory flow, considerably more power is available to the shorter and more highly blocked turbine arrays.

Impact of the Level of Approximation on Modeling Flushing Waves

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
P. Staufer ◽  
J. Dettmar ◽  
J. Pinnekamp
Keyword(s):  
Shear Stress ◽  
Numerical Models ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Bottom Shear Stress ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Successful Operation ◽  
One Dimensional ◽  
The One

Sewer cleaning with the means of flushing offers the possibility to place sewers free of deposit if flushing waves are generated continuously or quasi-continuously by suitable flushing devices. Numerical investigations should be carried out regarding different hydraulic circumstances because sewer networks consist of various compounds with complex geometries e.g. cross-section alignment or special structures. To accomplish a stable and successful operation of flushing devices it seems necessary to use different level of approximation on modelling flushing waves. Thereby both accuracy and running-time of simulations with numerical models will be optimized. This paper presents differences and similarities of the simulation results of a one-dimensional and a three-dimensional model of flushing wave within a big sized sewer. As assumed the one-dimensional model becomes less accurate when the complexity of the geometry increases. The three-dimensional model shows an underestimation of velocity and bottom shear-stress at the flushing head due to energy losses within the water body. Contrary, the one-dimensional model overestimates bottom shear-stress at the flushing head because of a stationary basic approach which is used. However, real highly resolved measurements of bottom shear-stresses are required to confirm the results in detail.

scholarly journals One and Two-Dimensional Hydraulic Simulation of a Reach in Al-Gharraf River

2020 ◽  
Vol 26 (7) ◽  
pp. 28-44
Author(s):  
Mariam H. Daham ◽  
Basim Sh. Abed
Keyword(s):  
Numerical Models ◽  
Two Dimensional ◽  
Hydraulic Characteristics ◽  
Dimensional Model ◽  
Hydraulic Simulation ◽  
One Dimensional ◽  
Two Dimensional Model ◽  
Average Water ◽  
The One ◽  
Manning Roughness

        One and two-dimensional hydraulic models simulations are important to specify the hydraulic characteristics of unsteady flow in Al-Gharraf River in order to define the locations that facing problems and suggesting the necessary treatments. The reach in the present study is 58200m long and lies between Kut and Hai Cities. Both numerical models were simulated using HEC-RAS software, 5.0.4, with flow rates ranging from 100 to 350 m3/s. Multi-scenarios of gates openings of Hai Regulator were applied. While the openings of Al-Gharraf Head Regulator were ranged between 60cm to fully opened. The suitable manning roughness for the unsteady state was 0.025. The obtained results show that the average velocities for the one-dimensional model were ranged between 0.36 and 0.5 m/s,  and the average water surface elevations range between 15.14 m and 17.84 m. While these values ranged between 0.25 and 0.44 m/s and 14.125 and 18.82 m respectively for the two-dimensional model. The simulation results of the two-dimensional model were more accurate than their corresponding one-dimensional model, due to more agreement of these values with measured values, which achieved minimum values of the root mean square error and the determination coefficient.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

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