The Experts below are selected from a list of 184617 Experts worldwide ranked by ideXlab platform
Charles Meneveau - One of the best experts on this subject based on the ideXlab platform.
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A dynamic flame surface density Model for large eddy simulation of turbulent premixed combustion
Physics of Fluids, 2004Co-Authors: Ronnie Knikker, Denis Veynante, Charles MeneveauAbstract:A dynamic formulation for a previously developed coupled fractal/Similarity Model for large eddy simulation of premixed combustion is proposed. In this formulation, the fractal dimension is obtained dynamically from the resolved scales, leaving the inner cutoff scale, representative for the smallest flame structures, as the only parameter to be prescribed. The fractal Model provides an accurate estimate for the mean flame surface, whereas the Similarity Model predicts its spatial distribution.
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A priori testing of a Similarity Model for large eddysimulations of turbulent premixed combustion
Proceedings of the Combustion Institute, 2002Co-Authors: R. Knikker, Denis Veynante, Charles MeneveauAbstract:Large eddy simulation, where large coherent structures are explicitly computed whereas the effects ofsmaller ones are Modeled, appears as a very promising tool to numerically describe turbulent combustion. However, this approach requires the Modeling of the unresolved reaction rate (i.e., reaction rate at scales unresolved during the simulation). In this paper, a Similarity Model, where the unresolved scales are assumed to behave like scales slightly larger than the cutoff scale, is proposed to estimate the subgridscale flame surface density. The Model parameter is Modeled assuming that the flame front behaves like a fractal surface at scales larger than a cutoff scale of the order of the laminar flame thickness. This Model is tested against experimental data obtained using planar laser-induced fluorescence on the OH radical in a turbulent premixed propane/air flame. Promising results are found: the Similarity Model reproduces correctly the locations of the unresolved reaction rate, whereas the fractal scaling analysis provides a very good estimate of the Model parameter.
Peter Nielsen - One of the best experts on this subject based on the ideXlab platform.
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Surf zone states and energy dissipation regimes-a Similarity Model
Coastal Engineering Journal, 2013Co-Authors: Hannah E Power, David P. Callaghan, Tom E Baldock, Peter NielsenAbstract:A Similarity parameter is derived to describe surf zone dissipation using the classical energy dissipation Model for surf zone bores. This parameter can also be interpreted as a relative beach slope parameter, β γ, and, for shallow water sinusoidal waves, is the ratio of the local beach slope and the local wave steepness (H/L). βγ = 1 defines the boundary between two different energy dissipation regimes. Conditions with βγ 1 represent under-dissipative conditions, where the bore Model provides insufficient dissipation for depth-limited conditions to occur. Conditions with βγ = 1 at the breakpoint lead to locally saturated but not depth-limited surf. Hence, the new Similarity parameter distinguishes between saturated and unsaturated surf conditions. Based on this bore dissipation Model, an analytical Model for the wave height transformation of monochromatic waves on planar beaches is derived. The cross-shore variation in wave height obtained from this Model show different functional forms; concave upward for over-dissipative conditions and convex upward for under-dissipative conditions. Further, the analytical Model shows that depth-limited conditions within the inner surf zone are not possible with this bore dissipation Model and the Model assumptions. Additional work is required to determine if this parameter is a useful predictor of other surf zone characteristics. Highlights: We derive a Similarity parameter to describe surf zone dissipation. The Similarity parameter defines the boundary of two dissipation regimes. The parameter distinguishes between saturated and unsaturated surf conditions. The classical bore dissipation Model cannot predict depth-limited wave heights on a plane beach.
Denis Veynante - One of the best experts on this subject based on the ideXlab platform.
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A dynamic flame surface density Model for large eddy simulation of turbulent premixed combustion
Physics of Fluids, 2004Co-Authors: Ronnie Knikker, Denis Veynante, Charles MeneveauAbstract:A dynamic formulation for a previously developed coupled fractal/Similarity Model for large eddy simulation of premixed combustion is proposed. In this formulation, the fractal dimension is obtained dynamically from the resolved scales, leaving the inner cutoff scale, representative for the smallest flame structures, as the only parameter to be prescribed. The fractal Model provides an accurate estimate for the mean flame surface, whereas the Similarity Model predicts its spatial distribution.
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A priori testing of a Similarity Model for large eddysimulations of turbulent premixed combustion
Proceedings of the Combustion Institute, 2002Co-Authors: R. Knikker, Denis Veynante, Charles MeneveauAbstract:Large eddy simulation, where large coherent structures are explicitly computed whereas the effects ofsmaller ones are Modeled, appears as a very promising tool to numerically describe turbulent combustion. However, this approach requires the Modeling of the unresolved reaction rate (i.e., reaction rate at scales unresolved during the simulation). In this paper, a Similarity Model, where the unresolved scales are assumed to behave like scales slightly larger than the cutoff scale, is proposed to estimate the subgridscale flame surface density. The Model parameter is Modeled assuming that the flame front behaves like a fractal surface at scales larger than a cutoff scale of the order of the laminar flame thickness. This Model is tested against experimental data obtained using planar laser-induced fluorescence on the OH radical in a turbulent premixed propane/air flame. Promising results are found: the Similarity Model reproduces correctly the locations of the unresolved reaction rate, whereas the fractal scaling analysis provides a very good estimate of the Model parameter.
T. Kubota - One of the best experts on this subject based on the ideXlab platform.
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Mobility performance evaluation of planetary rover with Similarity Model experiment
IEEE International Conference on Robotics and Automation 2004. Proceedings. ICRA '04. 2004, 2004Co-Authors: Y. Kuroda, Tadashi Teshima, Y. Sato, T. KubotaAbstract:In order to carry out experiments many times on the Earth in consideration of the difference of gravitational acceleration to design the rover properly, we introduce Similarity law to design and construct the experimental Models. We have produced two experimental Models of the planetary rover with 5-wheel suspension system (called "PEGASUS") and 4WD system under for 1G and 1/2G gravity. We have carried out a low-gravity flight experiment in various parameters using the Model on the airplane. Assuming that Similarity law is true under every gravity environment, we have made relative evaluation on a degree of mobility by the difference of mobility systems. In the result of the flight experiment, it is show that PEGASUS is able to successfully move better than 4WD.
Hannah E Power - One of the best experts on this subject based on the ideXlab platform.
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Surf zone states and energy dissipation regimes-a Similarity Model
Coastal Engineering Journal, 2013Co-Authors: Hannah E Power, David P. Callaghan, Tom E Baldock, Peter NielsenAbstract:A Similarity parameter is derived to describe surf zone dissipation using the classical energy dissipation Model for surf zone bores. This parameter can also be interpreted as a relative beach slope parameter, β γ, and, for shallow water sinusoidal waves, is the ratio of the local beach slope and the local wave steepness (H/L). βγ = 1 defines the boundary between two different energy dissipation regimes. Conditions with βγ 1 represent under-dissipative conditions, where the bore Model provides insufficient dissipation for depth-limited conditions to occur. Conditions with βγ = 1 at the breakpoint lead to locally saturated but not depth-limited surf. Hence, the new Similarity parameter distinguishes between saturated and unsaturated surf conditions. Based on this bore dissipation Model, an analytical Model for the wave height transformation of monochromatic waves on planar beaches is derived. The cross-shore variation in wave height obtained from this Model show different functional forms; concave upward for over-dissipative conditions and convex upward for under-dissipative conditions. Further, the analytical Model shows that depth-limited conditions within the inner surf zone are not possible with this bore dissipation Model and the Model assumptions. Additional work is required to determine if this parameter is a useful predictor of other surf zone characteristics. Highlights: We derive a Similarity parameter to describe surf zone dissipation. The Similarity parameter defines the boundary of two dissipation regimes. The parameter distinguishes between saturated and unsaturated surf conditions. The classical bore dissipation Model cannot predict depth-limited wave heights on a plane beach.
