Institution
Swedish Defence Research Agency
Government•Stockholm, Sweden•
About: Swedish Defence Research Agency is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Radar & Laser. The organization has 1413 authors who have published 2731 publications receiving 56083 citations. The organization is also known as: Totalförsvarets forskningsinstitut.
Papers published on a yearly basis
Papers
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TL;DR: Large Eddy Simulations of a swirl-stabilized natural gas-air flame in a laboratory gas turbine combustor is performed using six different LES combustion models to provide a head-to-head comparative study.
Abstract: Large Eddy Simulations (LES) of a swirl-stabilized natural gas-air flame in a laboratory gas turbine combustor is performed using six different LES combustion models to provide a head-to-head comparative study. More specifically, six finite rate chemistry models, including the thickened flame model, the partially stirred reactor model, the approximate deconvolution model and the stochastic fields model have been studied. The LES predictions are compared against experimental data including velocity, temperature and major species concentrations measured using Particle Image Velocimetry (PIV), OH Planar Laser-Induced Fluorescence (OH-PLIF), OH chemiluminescence imaging and one-dimensional laser Raman scattering. Based on previous results a skeletal methane-air reaction mechanism based on the well-known Smooke and Giovangigli mechanism was used in this work. Two computational grids of about 7 and 56 million cells, respectively, are used to quantify the influence of grid resolution. The overall flow and flame structures appear similar for all LES combustion models studied and agree well with experimental still and video images. Takeno flame index and chemical explosives mode analysis suggest that the flame is premixed and resides within the thin reaction zone. The LES results show good agreement with the experimental data for the axial velocity, temperature and major species, but differences due to the choice of LES combustion model are observed and discussed. Furthermore, the intrinsic flame structure and the flame dynamics are similarly predicted by all LES combustion models examined. Within this range of models, there is no strong case for deciding which model performs the best.
42 citations
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TL;DR: In this article, the authors compare the performance of three different computational fluid dynamics codes using a common unstructured grid for steady and unsteady viscous flow simulations of a full-scale, semispan, and full-span model of the F-16XL-1 aircraft.
Abstract: Steady and unsteady viscous flow simulations of a full-scale, semispan, and full-span model of the F-16XL-1 aircraft are performed with three different computational fluid dynamics codes using a common unstructured grid. Six different flight conditions are considered. They represent Reynolds and Mach number combinations at subsonic speeds, with and without sideslip. The steady computations of the flow at these flight conditions are made with several Reynolds-averaged Navier-Stokes turbulence models of different complexity. Detached-eddy simulation, delayed detached-eddy simulation, and an algebraic hybrid Reynolds-averaged Navier-Stokes/large-eddy simulation model are used to quantify unsteady effects at the same flight conditions. The computed results are compared with flight-test data in the form of surface pressures, skin friction, and boundary-layer velocity profiles. The focus of the comparison is on turbulence modeling effects and effects of unsteadiness. The overall agreement with flight data is good, with no clear trend as to which physical modeling approach is superior for this class of flow. The Reynolds-averaged Navier-Stokes turbulence models perform well in predicting the flow in an average sense. However, some of the flow conditions involve locally unsteady flow over the aircraft, which are held responsible for the scatter between the different turbulence modeling approaches. The detached-eddy simulations are able to quantify the unsteady effects, although they are not consistently better than the Reynolds-averaged Navier-Stokes turbulence models in predicting the flow in an average sense in these flow regions. Detached-eddy simulation fails to predict boundary-layer profiles consistently over a range of flow regimes, with delayed detached-eddy simulation and hybrid Reynolds-averaged Navier-Stokes/large-eddy simulation models offering a remedy to recover some of the predictive capabilities of the underlying Reynolds-averaged Navier-Stokes turbulence model. Nonetheless, the confidence in the predictive capabilities of the computational fluid dynamics codes with regard to complex vortical flowfields around high-performance aircraft of this planform increased significantly during this study.
42 citations
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TL;DR: In this article, wood fuel powders cut in different mills were combusted in a 150kW burner to study emissions, furnace temperature and burnout as a function of particle size distribution and particle shape.
42 citations
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07 Oct 2010TL;DR: The first steps of laser radar are discussed with the examples from range finding and designation as discussed by the authors, followed by success in field tests and further fast development provided their wide use, including incorporation of range and velocity data into the image information.
Abstract: The first steps of laser radar are discussed with the examples from range finding and designation. The followed
successes in field tests and further fast development provided their wide use. Coherent laser radar, developed almost
simultaneously, tried the ideas from microwaves including chirp technology for pulse compression, and Doppler mode
of operation. This latter found a unique implementation in a cruise missile. In many applications, environmental studies
very strongly rely upon the lidars sensing the wind, temperature, constituents, optical parameters. Lidars are used in the
atmosphere and in the sea water measurements. Imaging and mapping is an important role prescribed to ladars. One of
the prospective trends in laser radar development is incorporation of range and velocity data into the image information.
Deep space program, even having not come to the finish, gave a lot for 3D imaging. Gated imaging, as one of the 3D
techniques, demonstrated its prospects (seeing through scattering layers) for military and security usage. Synthetic
aperture laser radar, which had a long incubation period, started to show first results, at least in modeling. Coherent laser
radar baptized as the optical coherence tomography, along with the position sensitive laser radar, synthetic aperture laser
radar, multispectral laser radar demonstrated very pragmatic results in the micro-scale applications.
42 citations
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TL;DR: Weis and Hutter as discussed by the authors obtained an implicit algebraic Reynolds stress model from a differential Reynolds stress transport equation valid in an arbitrarily rotating fluid machine, which they used to obtain an implicit linear model of the transport equation.
Abstract: Weis & Hutter (J. Fluid Mech. vol. 476, 2003, p. 63) obtained an implicit algebraic Reynolds stress model from a differential Reynolds stress transport equation valid in an arbitrarily rotating ...
42 citations
Authors
Showing all 1417 results
Name | H-index | Papers | Citations |
---|---|---|---|
Anders Larsson | 80 | 1307 | 33995 |
Anders Johansson | 75 | 538 | 21709 |
Anders Eriksson | 68 | 679 | 19487 |
Dan S. Henningson | 66 | 369 | 19038 |
Bengt Johansson | 66 | 635 | 19206 |
Anders Sjöstedt | 63 | 196 | 11422 |
Björn Johansson | 62 | 637 | 16030 |
Mats Gustafsson | 61 | 520 | 18574 |
D. G. Joakim Larsson | 58 | 151 | 13687 |
Anders Larsson | 54 | 198 | 55761 |
Mats Tysklind | 53 | 250 | 17534 |
Jerker Fick | 51 | 143 | 8787 |
Erik Johansson | 50 | 114 | 9437 |
Göran Finnveden | 49 | 193 | 12663 |
Ian A. Nicholls | 45 | 194 | 7522 |