scholarly journals Evaluating the effects of microphysical complexity in idealised simulations of trade wind cumulus using the Factorial Method

2010 ◽  
Vol 10 (10) ◽  
pp. 23497-23537 ◽  
Author(s):  
C. Dearden ◽  
P. J. Connolly ◽  
T. W. Choularton ◽  
P. R. Field
Keyword(s):  
State Of The Art ◽  
Model Development ◽  
Cloud Base ◽  
Trade Wind ◽  
One Dimensional ◽  
Surface Precipitation ◽  
Factorial Method ◽  
Modelling Framework ◽  
Development Tool ◽  
The Impact

Abstract. The effect of microphysical and environmental factors on the development of precipitation in warm idealised clouds are explored using an idealised process modelling framework. A simple one-dimensional column model is used to drive a suite of microphysics schemes including a flexible multi-moment bulk scheme (including both single and dual moment liquid water) and a state-of-the-art bin-resolved scheme with explicit treatments of liquid and aerosol. The Factorial Method is employed to quantify and compare the sensitivities of each scheme under a set of controlled conditions, in order to isolate the effect of additional microphysical complexity in terms of the impact on surface precipitation. For the schemes considered, and in the absence of entrainment, surface precipitation totals were found to depend increasingly on the meteorological conditions as the level of microphysical complexity is increased. The dual-moment liquid bulk scheme was shown to provide the best agreement with the bin scheme when the cloud base updraught speeds are relatively weak. At higher updraughts, all schemes show that the sensitivity to the magnitude of vertical velocity reduces dramatically, and any subsequent change in precipitation is governed almost entirely by the change in aerosol concentration. However the effect of changes in temperature were found to be underestimated in the bulk schemes compared to the bin scheme; this can be accounted for through differences in the depletion of rain below cloud base by evaporation. Collectively, these results demonstrate the usefulness of the Factorial Method as a model development tool for quantitatively comparing and contrasting the behaviour of microphysics schemes of differing levels of complexity within a specified parameter space.

scholarly journals Evaluating the effects of microphysical complexity in idealised simulations of trade wind cumulus using the Factorial Method

2011 ◽  
Vol 11 (6) ◽  
pp. 2729-2746 ◽  
Author(s):  
C. Dearden ◽  
P. J. Connolly ◽  
T. W. Choularton ◽  
P. R. Field
Keyword(s):  
Model Development ◽  
Trade Wind ◽  
One Dimensional ◽  
Surface Precipitation ◽  
Factorial Method ◽  
Modelling Framework ◽  
Development Tool ◽  
Single Moment ◽  
Kinematic Modelling ◽  
The Impact

Abstract. The effect of microphysical and environmental factors on the development of precipitation in warm idealised cloud is explored using a kinematic modelling framework. A simple one-dimensional column model is used to drive a suite of microphysics schemes including a flexible multi-moment bulk scheme (including both single and dual moment cloud liquid water) and a state-of-the-art bin-resolved scheme with explicit treatments of liquid and aerosol. The Factorial Method is employed to quantify and compare the sensitivities of each scheme under a set of controlled conditions, in order to isolate the effect of additional microphysical complexity in terms of the impact on surface precipitation. At relatively low updraught speeds, the sensitivity of the bulk schemes was found to depend on the assumptions made with regards the treatment of droplet activation. It was possible to achieve a much closer agreement between the single and dual moment bulk schemes by tuning the specified droplet number concentration in the single moment scheme, suggesting that a diagnostic representation of droplet number may be an acceptable alternative to the more expensive prognostic option. However the effect of changes in CCN concentration were found to produce a relatively stronger effect on precipitation in the bulk schemes compared to the bin scheme; this is believed to be a consequence of differences in the treatment of drop growth by collision and coalescence. Collectively, these results demonstrate the usefulness of the Factorial Method as a model development tool for quantitatively comparing and contrasting the behaviour of microphysics schemes of differing levels of complexity within a specified parameter space.

Performance Modeling of Desiccant Wheels: 1 — Model Development

2008 ◽  
Author(s):  
Chaoqin Zhai ◽  
David H. Archer ◽  
John C. Fischer
Keyword(s):  
Model Development ◽  
Axial Direction ◽  
Performance Model ◽  
Design Parameters ◽  
Residual Water ◽  
One Dimensional ◽  
Operating Variables ◽  
Steady State Operation ◽  
Rotary Speed ◽  
The Impact

This paper presents the development of an equation based model to simulate the combined heat and mass transfer in the desiccant wheels. The performance model is one dimensional in the axial direction. It applies a lumped formulation in the thickness direction of the desiccant and the substrate. The boundary conditions of this problem represent the inlet outside/process and building exhaust/regeneration air conditions as well as the adiabatic condition of the two ends of the desiccant composite. The solutions of this model are iterated until the wheel reaches periodic steady state operation. The modeling results are obtained as the changes of the outside/process and building exhaust/regeneration air conditions along the wheel depth and the wheel rotation. This performance model relates the wheel’s design parameters, such as the wheel dimension, the channel size and the desiccant properties, and the wheel’s operating variables, such as the rotary speed and the regeneration air flowrate, to its operating performance. The impact of some practical issues, such as wheel purge, residual water in the desiccant and the wheel supporting structure, on the wheel performance has also been investigated.

A Physics-Based Dynamic Model for Boilers: Part 1 — Model Development and Validation

2017 ◽  
Author(s):  
Matthew J. Blom ◽  
Michael J. Brear ◽  
Chris G. Manzie ◽  
Ashley P. Wiese
Keyword(s):  
Steady State ◽  
Power Plant ◽  
Electrical Power ◽  
Model Development ◽  
Two Phase ◽  
One Dimensional ◽  
Modelling Framework ◽  
Singular Perturbation Analysis ◽  
Fluid Properties ◽  
Development And Validation

This paper is the first part of a two part study that develops, validates and integrates a one-dimensional, physics-based, dynamic boiler model suitable for application with model based control. Part 1 of this study extends and validates the existing, higher order modelling framework of Badmus et. al. [1] to boilers. This requires derivation of particular, one-dimensional forms of the equations for heat, mass and momentum transfer in single (liquid and gas) phase and two phase fluids with real fluid properties. The so-called ‘forcing term’ mapping functions in these equations only require knowledge of steady state system behaviour, and so can be obtained from steady state measurements throughout the boiler system. Additional models are also presented for other boiler components, including the steam drum in sub-critical boilers. The overall framework is then used to develop and validate a model of a GW scale, sub-critical boiler in an operating, electrical power plant. Overall, the model achieves reasonable agreement with the power plant dynamics during normal transient operations, including acceptable tracking of the drum dynamics and the steam at the boiler outlet. As such, this modelling framework appears suitable for developing models of sufficient fidelity yet retain an appropriate form for model reduction using singular perturbation analysis techniques, as demonstrated in Part 2 [2] of this study.

scholarly journals Deep Convection Triggering by Boundary Layer Thermals. Part II: Stochastic Triggering Parameterization for the LMDZ GCM

2014 ◽  
Vol 71 (2) ◽  
pp. 515-538 ◽  
Author(s):  
Nicolas Rochetin ◽  
Jean-Yves Grandpeix ◽  
Catherine Rio ◽  
Fleur Couvreux
Keyword(s):  
General Circulation ◽  
Deep Convection ◽  
Circulation Model ◽  
Cloud Base ◽  
Trade Wind ◽  
Shallow Convection ◽  
Model Framework ◽  
Main Hypothesis ◽  
Single Column ◽  
The Impact

Abstract This paper presents a stochastic triggering parameterization for deep convection and its implementation in the latest standard version of the Laboratoire de Météorologie Dynamique–Zoom (LMDZ) general circulation model: LMDZ5B. The derivation of the formulation of this parameterization and the justification, based on large-eddy simulation results, for the main hypothesis was proposed in Part I of this study. Whereas the standard triggering formulation in LMDZ5B relies on the maximum vertical velocity within a mean bulk thermal, the new formulation presented here (i) considers a thermal size distribution instead of a bulk thermal, (ii) provides a statistical lifting energy at cloud base, (iii) proposes a three-step trigger (appearance of clouds, inhibition crossing, and exceeding of a cross-section threshold), and (iv) includes a stochastic component. Here the complete implementation is presented, with its coupling to the thermal model used to treat shallow convection in LMDZ5B. The parameterization is tested over various cases in a single-column model framework. A sensitivity study to each parameter introduced is also carried out. The impact of the new triggering is then evaluated in the single-column version of LMDZ on several case studies and in full 3D simulations. It is found that the new triggering (i) delays deep convection triggering, (ii) suppresses it over oceanic trade wind cumulus zones, (iii) increases the low-level cloudiness, and (iv) increases the convective variability. The scale-aware nature of this parameterization is also discussed.

Factors Determining the Impact of Aerosols on Surface Precipitation from Clouds: An Attempt at Classification

2008 ◽  
Vol 65 (6) ◽  
pp. 1721-1748 ◽  
Author(s):  
A. P. Khain ◽  
N. BenMoshe ◽  
A. Pokrovsky
Keyword(s):  
Forest Fires ◽  
Large Scale ◽  
Cloud Model ◽  
Aerosol Concentration ◽  
Cloud Base ◽  
Atmospheric Conditions ◽  
Diffusional Growth ◽  
Surface Precipitation ◽  
Freezing Level ◽  
The Impact

Abstract The simulation of the dynamics and the microphysics of clouds observed during the Large-Scale Biosphere–Atmosphere Experiment in Amazonia—Smoke, Aerosols, Clouds, Rainfall, and Climate (LBA–SMOCC) campaign, as well as extremely continental and extremely maritime clouds, is performed using an updated version of the Hebrew University spectral microphysics cloud model (HUCM). A new scheme of diffusional growth allows the reproduction of in situ–measured droplet size distributions including those formed in extremely polluted air. It was shown that pyroclouds forming over the forest fires can precipitate. Several mechanisms leading to formation of precipitation from pyroclouds are considered. The mechanisms by which aerosols affect the microphysics and precipitation of warm cloud-base clouds have been investigated by analyzing the mass, heat, and moisture budgets. The increase in aerosol concentration increases both the generation and the loss of the condensate mass. In the clouds developing in dry air, the increase in the loss is dominant, which suggests a decrease in the accumulated precipitation with the aerosol concentration increase. On the contrary, an increase in aerosol concentration in deep maritime clouds leads to an increase in precipitation. The precipitation efficiency of clouds in polluted air is found to be several times lower than that of clouds forming in clean air. A classification of the results of aerosol effects on precipitation from clouds of different types developing in the atmosphere with high freezing level (about 4 km) is proposed. The role of air humidity and other factors in precipitation’s response to aerosols is discussed. The analysis shows that many discrepancies between the results reported in different observational and numerical studies can be attributed to the different atmospheric conditions and cloud types analyzed.

scholarly journals On the Fidelity of Large-Eddy Simulation of Shallow Precipitating Cumulus Convection

2011 ◽  
Vol 139 (9) ◽  
pp. 2918-2939 ◽  
Author(s):  
Georgios Matheou ◽  
Daniel Chung ◽  
Louise Nuijens ◽  
Bjorn Stevens ◽  
Joao Teixeira
Keyword(s):  
Large Eddy Simulation ◽  
Liquid Water ◽  
Cloud Cover ◽  
Scale Model ◽  
Trade Wind ◽  
Numerical Dissipation ◽  
Surface Precipitation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Impact

The present study considers the impact of various choices pertaining to the numerical solution of the governing equations on large-eddy simulation (LES) prediction and the association of these choices with flow physics. These include the effect of dissipative versus nondissipative advection discretizations, different implementations of the constant-coefficient Smagorinsky subgrid-scale model, and grid resolution. Simulations corresponding to the trade wind precipitating shallow cumulus composite case of the Rain in Cumulus over the Ocean (RICO) field experiment were carried out. Global boundary layer quantities such as cloud cover, liquid water path, surface precipitation rate, power spectra, and the overall convection structure were used to compare the effects of different discretization implementations. The different discretization implementations were found to exert a significant impact on the LES prediction even for the cases where the process of precipitation was not included. Increasing numerical dissipation decreases cloud cover and surface precipitation rates. For nonprecipitating cases, grid convergence is achieved for grid spacings of 20 m. Cloud cover was found to be particularly sensitive, exhibiting variations between different resolution runs even when the mean liquid water profile had converged.

An Exploratory Study of the Impact of Servitization on Customer Perceived Value

2015 ◽  
Vol 760 ◽  
pp. 727-732 ◽  
Author(s):  
Gheorghe Militaru
Keyword(s):  
Business Model ◽  
Service Providers ◽  
State Of The Art ◽  
Model Development ◽  
Manufacturing Companies ◽  
Product Complexity ◽  
Customer Perceived Value ◽  
New Business ◽  
The Impact ◽  
Business Model Development

The aim of this paper is to explore how manufacturers becoming service providers by adding service offerings to their total offering. We investigate the extent to which existing internal capablity of manufacturing companies and external factors affect the level of servitization. This paper presents the state-of-the art of servitization within a manufacturing context. Our findings indicate a need for recursive iterations between different elements of separated and integrated processes in line with new business model. Thus, servitization is pozitiviley related to business model and product complexity. There is a need to improve the connective mechanisms and dynamics involved in business model development. Finally, this paper contributes to the development and rafinement of the process to shift from selling products to selling integrated products and services that deliver value in use for customers.

Interaction Process Model – ESM Quality Model Development Tool

2020 ◽  
Vol 25 (1) ◽  
pp. 10-17
Author(s):  
B.V. Boytsov ◽  
◽  
G.S. Zhetessova ◽  
M.K. Ibatov ◽  
◽  
...  
Keyword(s):  
Process Model ◽  
Swot Analysis ◽  
Statistical Data ◽  
Model Development ◽  
Interaction Process ◽  
Educational Process ◽  
Quality Model ◽  
Development Tool ◽  
The Republic ◽  
Education Science

The article discusses the methodology and provides the results of a multivariate SWOT analysis for a scientific and manufacturing educational process based on a set of regulatory and strategic documents, statistical data of the Republic of Kazakhstan; The main conclusions and description of the generated matrices for the subjects of interaction within the hierarchical triangle «Education – Science – Manufacturing (ESM)» are given.

State-of-the-Art of Modeling Surface Water Impoundments

1982 ◽  
Vol 14 (1-2) ◽  
pp. 241-261 ◽  
Author(s):  
P A Krenkel ◽  
R H French
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
State Of The Art ◽  
Rate Coefficients ◽  
Two Dimensional ◽  
One Dimensional ◽  
Integral Energy ◽  
Range Of Values ◽  
Dimensional Integral ◽  
Water Impoundment

The state-of-the-art of surface water impoundment modeling is examined from the viewpoints of both hydrodynamics and water quality. In the area of hydrodynamics current one dimensional integral energy and two dimensional models are discussed. In the area of water quality, the formulations used for various parameters are presented with a range of values for the associated rate coefficients.

scholarly journals Comparison of Industrial Quenching Oils

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 250
Author(s):  
Jiří Hájek ◽  
Zaneta Dlouha ◽  
Vojtěch Průcha
Keyword(s):  
State Of The Art ◽  
Cooling Capacity ◽  
Steel Grade ◽  
Cooling Curves ◽  
Cooling Process ◽  
Industrial Practice ◽  
Product Size ◽  
Cct Curve ◽  
Hardening Power ◽  
The Impact

This article is a response to the state of the art in monitoring the cooling capacity of quenching oils in industrial practice. Very often, a hardening shop requires a report with data on the cooling process for a particular quenching oil. However, the interpretation of the data can be rather difficult. The main goal of our work was to compare various criteria used for evaluating quenching oils. Those of which prove essential for operation in tempering plants would then be introduced into practice. Furthermore, the article describes monitoring the changes in the properties of a quenching oil used in a hardening shop, the effects of quenching oil temperature on its cooling capacity and the impact of the water content on certain cooling parameters of selected oils. Cooling curves were measured (including cooling rates and the time to reach relevant temperatures) according to ISO 9950. The hardening power of the oil and the area below the cooling rate curve as a function of temperature (amount of heat removed in the nose region of the Continuous cooling transformation - CCT curve) were calculated. V-values based on the work of Tamura, reflecting the steel type and its CCT curve, were calculated as well. All the data were compared against the hardness and microstructure on a section through a cylinder made of EN C35 steel cooled in the particular oil. Based on the results, criteria are recommended for assessing the suitability of a quenching oil for a specific steel grade and product size. The quenching oils used in the experiment were Houghto Quench C120, Paramo TK 22, Paramo TK 46, CS Noro MO 46 and Durixol W72.

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