• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.305-306
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• 2006

Developed in this study is a nonlinear Ekman pumping model to be used in simulating the rotating flows with quasi-three-dimensional Navier-Stokes equations. In this model, the Ekman pumping velocity is given from the solution of the Ekman boundary-layer equations for the region adjacent to the bottom wall of the flow domain; the boundary-layer equations are solved in the momentum-integral form. The developed model is then applied to rotating flows in a rectangular container receiving a time-periodic forcing. By comparing our results with the DNS and experimental data we have validated the developed model. We also compared our results with those given from the classical Ekman pumping model. It was found that our model can predict tile rotating flows more precisely than the classical linear model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.6 s.249
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• pp.568-577
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• 2006

Developed in this study is a nonlinear Ekman pumping model to be used in simulating the rotating flows with quasi-three-dimensional Navier-Stokes equations. In this model, the Ekman pumping velocity is given from the solution of the Ekman boundary-layer equations for the region adjacent to the bottom wall of the flow domain; the boundary-layer equations are solved in the momentum-integral form. The developed model is then applied to rotating flows in a rectangular container receiving a time-periodic forcing. By comparing our results with the DNS and experimental data we have validated the developed model. We also compared our results with those given from the classical Ekman pumping model. It was found that our model can predict the rotating flows more precisely than the classical linear model.

• Journal of Forest and Environmental Science
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• v.34 no.4
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• pp.313-320
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• 2018

Tectona grandis (teak) is one of the most important timber species worldwide and India is one of the major teak growing countries. Though some volume equations were developed for teak in India but the models developed were neither evaluated using robust statistical criteria nor validated. Hence, the objective of this study was to develop statistically tested appropriate volume equation to predict total wood volume (over- and under-bark) for teak trees in Gujarat. A total of 41 trees with age varying from 15 to 33 years and diameter at breast height (dbh) from 7.3 to 30.8 cm were felled for the purpose. Linear and non-linear equations were used to model the relationship of the total wood volume with respect to dbh and total height. The equations tested mostly fitted well to the data. Model evaluation and validation indicated that models should be calibrated with local data for greater accuracy in the prediction.

• Journal of the korean society of oceanography
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• v.38 no.4
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• pp.185-210
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• 2003

This paper describes and assesses the parameterisation of MP, the microplankton compartment of the carbon­nitrogen microplankton­detritus model. The compartment is 'the microbial loop in a box' and includes pelagic bacteria and protozoa as well as phytoplankton. The paper presents equations and parameter values for the autotroph and microheterotroph components of the microplankton. Equations and parameter values for the microplankton as a whole are derived on the assumption of a constant 'heterotroph fraction'. The autotroph equations of MP allow variation in the ratios of nutrient elements to carbon, and are largely those of the 'cell­quota, threshold­limitation' algal growth model, which can deal with potential control of growth by several nutrients and light. The heterotroph equations, in contrast, assume a constant elemental composition. Nitrogen is used as the limiting nutrient in most of the model description, and is special in that MP links chlorophyll concentration to the autotroph nitrogen quota.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.2
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• pp.80-85
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• 2003

This paper describes the generation and maximum run-up heights of cnoidal waves with varying periods by the numerical model. The model solves the Reynolds equations and the k-epsilon equations for the turbulent analysis. To track free surface displacements, the volume of fluid(VOF) method is employed. It is shown that profiles of the numerically generated cnoidal waves agree well with analytical solutions. The computed maximum run-up heights are compared with laboratory measurements and those of the boundary element method. The present model provides more agreeable results to laboratory measurements that the boundary element model.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.109-118
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• 2013

The absence of a simple and general analytical model has been a problem in the design and analysis of desiccant-assisted air-conditioning systems. In this study, such an analytical model has been developed based on the approximate integral solution of the coupled transient ordinary differential equations for the heat and mass transfer processes in a desiccant wheel. It turned out that the initial conditions should be determined by the solution of four linear algebraic equations including the heat and mass transfer equations for the air flow as well as the energy and mass conservation equations for the desiccant bed. It is also shown that time-averaged exit air temperature and humidity relations could be given in terms of the heat and mass transfer effectiveness.

• Journal of Korea Water Resources Association
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• v.40 no.5
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• pp.397-407
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• 2007

The deposition of sewer solids during dry weather in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. In order to solve these problems and to manage sewer systems efficiently, development of estimation equations for solid sediments In sewer systems is needed. However, estimation of solid sediments has performed using specific methods such as computer model before the development of estimation equations. In this study, solid sediments in sewer systems were estimated using MOUSE model for Gunja drainage basin in Korea and the estimated results were verified using estimation equations developed by the U.S. Environmental Protection Agency. As results, the estimated values using MOUSE model are smaller than that of equations developed in 1977 but greater than that of equations developed in 1984. Although the comparison between simulated and measured solid deposition is difficult due to the absent of measurement data, the estimated values using MOUSE model is reliable and can be used to develop estimation equations for solid sediment in Gunja drainage basin.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.783-788
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• 2001

Choosing the most suitable mathematical model and relating this to turbulent tangential tensions model are very important in the investigations of turbulent two-phase flow. This paper considers two-fluid scheme. According to it, two phases have their own densities, velocities, and temperatures at any spatial point and at any moment. The equations of motion and heat transfer for each phase are linked with the forces of interaction between two phases. These forces are considered as predominant for the flow. As a closure in the system of motion equations, one modification of $K - {\epsilon}$ turbulent model is worked out. The modification uses two equations for turbulent kinetic energy of the phases and one - for the turbulent energy loss of main phase. This model can be set as a $K_g - K_p -{\epsilon}$ model. The modified model has been tested for both a two-phase non-isothermal flat jet and axially symmetrical jet. The numerical results are compared with the reference data revealing a good agreement between them.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.580-585
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• 2000

Recently TEIS model, Two-zone model aid Stanitz equations are often used for off-design performance prediction of centrifugal compressor and pump. The prediction results often agree well with experimental data. However these models and equations have some important variables which have a great influence on overall performance prediction me. But no systematic study about these variables has been performed. So, in this paper, a systematic study about these variables influence on overall performance prediction owe is peformed. Finally the meaning of the variables and the research to be undertaken are discussed.

• The Pure and Applied Mathematics
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• v.13 no.3 s.33
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• pp.217-225
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• 2006

We consider the nonrelativistic limit for the radial solutions to the self-dual equations in the self-dual Abelian Chern-Simons model. We achieve the limit by fixing the common maximum value of solutions.