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Stephane Zaleski - One of the best experts on this subject based on the ideXlab platform.

  • volume of fluid interface tracking with smoothed Surface stress methods for three dimensional flows
    Journal of Computational Physics, 1999
    Co-Authors: Denis Gueyffier, Ali Nadim, Jie Li, Ruben Scardovelli, Stephane Zaleski
    Abstract:

    Motivated by the need for three-dimensional methods for interface calculations that can deal with topology changes, we describe a numerical scheme, built from a volume-of-fluid interface tracking technique that uses a piecewise-linear interface calculation in each cell. Momentum balance is computed using explicit finite volume/finite differences on a regular cubic grid. Surface tension is implemented by the Continuous Surface stress or Continuous Surface force method. Examples and verifications of the method are given by comparing simulations to analytical results and experiments, for sedimenting droplet arrays and capillary waves at finite Reynolds number. In the case of a pinching pendant drop, both three-dimensional and axisymmetric simulations are compared to experiments. Agreement is found both before and after the reconnections.

  • volume of fluid interface tracking with smoothed Surface stress methods for three dimensional flows
    Journal of Computational Physics, 1999
    Co-Authors: Denis Gueyffier, Ali Nadim, Ruben Scardovelli, Stephane Zaleski
    Abstract:

    Motivated by the need for three-dimensional methods for interface calculations that can deal with topology changes, we describe a numerical scheme, built from a volume-of-fluid interface tracking technique that uses a piecewise-linear interface calculation in each cell. Momentum balance is computed using explicit finite volume/finite differences on a regular cubic grid. Surface tension is implemented by the Continuous Surface stress or Continuous Surface force method. Examples and verifications of the method are given by comparing simulations to analytical results and experiments, for sedimenting droplet arrays and capillary waves at finite Reynolds number. In the case of a pinching pendant drop, both three-dimensional and axisymmetric simulations are compared to experiments. Agreement is found both before and after the reconnections.

Denis Gueyffier - One of the best experts on this subject based on the ideXlab platform.

  • volume of fluid interface tracking with smoothed Surface stress methods for three dimensional flows
    Journal of Computational Physics, 1999
    Co-Authors: Denis Gueyffier, Ali Nadim, Jie Li, Ruben Scardovelli, Stephane Zaleski
    Abstract:

    Motivated by the need for three-dimensional methods for interface calculations that can deal with topology changes, we describe a numerical scheme, built from a volume-of-fluid interface tracking technique that uses a piecewise-linear interface calculation in each cell. Momentum balance is computed using explicit finite volume/finite differences on a regular cubic grid. Surface tension is implemented by the Continuous Surface stress or Continuous Surface force method. Examples and verifications of the method are given by comparing simulations to analytical results and experiments, for sedimenting droplet arrays and capillary waves at finite Reynolds number. In the case of a pinching pendant drop, both three-dimensional and axisymmetric simulations are compared to experiments. Agreement is found both before and after the reconnections.

  • volume of fluid interface tracking with smoothed Surface stress methods for three dimensional flows
    Journal of Computational Physics, 1999
    Co-Authors: Denis Gueyffier, Ali Nadim, Ruben Scardovelli, Stephane Zaleski
    Abstract:

    Motivated by the need for three-dimensional methods for interface calculations that can deal with topology changes, we describe a numerical scheme, built from a volume-of-fluid interface tracking technique that uses a piecewise-linear interface calculation in each cell. Momentum balance is computed using explicit finite volume/finite differences on a regular cubic grid. Surface tension is implemented by the Continuous Surface stress or Continuous Surface force method. Examples and verifications of the method are given by comparing simulations to analytical results and experiments, for sedimenting droplet arrays and capillary waves at finite Reynolds number. In the case of a pinching pendant drop, both three-dimensional and axisymmetric simulations are compared to experiments. Agreement is found both before and after the reconnections.

Junseok Kim - One of the best experts on this subject based on the ideXlab platform.

  • a Continuous Surface tension force formulation for diffuse interface models
    Journal of Computational Physics, 2005
    Co-Authors: Junseok Kim
    Abstract:

    We present a new Surface tension force formulation for a diffuse-interface model, which is derived for incompressible, immiscible Navier-Stokes equations separated by free interfaces. The classical infinitely thin boundary of separation between the two immiscible fluids is replaced by a transition region of small but finite width, across which the composition of the one of two fluids changes Continuously. Various versions of diffuse-interface methods have been used successfully for the numerical simulations of two phase fluid flows. These methods are robust, efficient, and capable of computing interface singularities such as merging and pinching off. But prior studies used modified Surface tension force formulations, therefore it is not straightforward to calculate pressure field because pressure includes the gradient terms resulting from the modified Surface tension term. The new formulation allows us to calculate the pressure field directly from the governing equations. Computational results showing the accuracy and effectiveness of the method are given for a drop deformation and Rayleigh capillary instability.

Kimjunseok - One of the best experts on this subject based on the ideXlab platform.

Janet F.c. Sham - One of the best experts on this subject based on the ideXlab platform.

  • Application of Continuous Surface temperature monitoring technique for investigation of nocturnal sensible heat release characteristics by building fabrics in Hong Kong
    Energy and Buildings, 2013
    Co-Authors: Janet F.c. Sham, Shazim Ali Memon, Tommy
    Abstract:

    Abstracts This study applied a novel technique, Continuous Surface temperature monitoring (CSTM) that uses infrared technology, for deriving in situ sensible heat released by different building fabrics in Kowloon Tong, Hong Kong. Five possible factors (finish materials, colors of finish materials, size of the building, orientation, and seasonal change) which may affect the cooling pattern/sensible heat release characteristics of building fabrics were studied. Cooling patterns of building fabrics of different sizes were found to be same. Therefore, CSTM technique can be applied to capture thermal data of a large number of buildings simultaneously for sensible heat analysis. In general, granite wall releases more sensible heat than aluminum and ceramic tile wall. It was found that difference between colors is not as significant as difference in finish materials. The maximum Surface temperature (peak) of walls facing east appears earlier than those facing west. Significant differences between energy released by building fabrics in hot and cold seasons was also found. However, the proportion of sensible heat released by the buildings to the global solar radiation (GSR) was similar in both seasons. Hence, it holds that the percent of sensible heat release against the total GSR is quite constant in hot and cold season.

  • Verification and application of Continuous Surface temperature monitoring technique for investigation of nocturnal sensible heat release characteristics by building fabrics
    Energy and Buildings, 2012
    Co-Authors: Janet F.c. Sham, Shazim Ali Memon
    Abstract:

    This study verified and applied a novel technique, Continuous Surface temperature monitoring (CSTM), developed by the authors to investigate the nocturnal sensible heat release characteristics by building fabrics. The CSTM technique uses infrared technology to estimate the nocturnal sensible heat (SH) transfer between building finishes materials and the surrounding environment without knowing the physical and thermal properties of the tested materials. Forty-seven repeated indoor test were carried out for verification with the traditional internal energy equation (IE method), i.e. the product of mass, heat capacity and temperature change. The results were delightfully satisfactory with only 1.8–5.2% of average discrepancy. The R2 value of 0.972 between the two methods suggested that the developed CSTM technique statistically fits well with sensible heat release calculated by IE method. This means that the CSTM technique can be used to estimate sensible heat release from an object with insignificant error. CSTM technique was then applied for investigating 13 building Surfaces in Central, Hong Kong. The findings proved that CSTM technique can be applied on number of buildings simultaneously to investigate the sensible heat release characteristics of different types of building fabrics. The results showed that granite walls release more sensible heat than ceramic walls.

  • Continuous Surface Temperature Monitoring to estimate sensible heat loss by building finishes
    Environmental Engineering and Management Journal, 2011
    Co-Authors: Janet F.c. Sham
    Abstract:

    This paper proposes a novel technique, Continuous Surface Temperature Monitoring (CSTM), that uses infrared technology to estimate the sensible heat (SH) transfer between building finishes materials and the surrounding environment without knowing the physical and thermal properties of the tested materials. It is critical to study the contribution of heat transferred by building fabrics to the Urban Heat Island (UHI) effect because of the increasing threat of global warming. One method to investigate this is to measure the SH loss of building fabrics. Its magnitude is the product of object’s mass, m, its specific heat, c, and its temperature change, ∆T. In this study, CSTM estimates the cooling curves of four building finishes tiles: concrete, marble, clay, and ceramic. The results are quite satisfactory in that there is only 11.86% error between the SH calculated by the formal Sensible eat equation (mc∆T) and the CSTM technique. The study also shows that clay tiles have the highest SH loss per unit volume to the surrounding environment, and the optimal parameter settings for the technique are discussed.