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| 2. |
- Lindgren, Lars-Erik, et al.
(författare)
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Approaches in computational welding mechanics applied to additive manufacturing : Review and outlook
- 2018
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Ingår i: Comptes rendus. Mecanique. - : Elsevier. - 1631-0721 .- 1873-7234. ; 346:11, s. 1033-1042
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Tidskriftsartikel (refereegranskat)abstract
- The development of computational welding mechanics (CWM) began more than four decades ago. The approach focuses on the region outside the molten pool and is used to simulate the thermo-metallurgical-mechanical behaviour of welded components. It was applied to additive manufacturing (AM) processes when they were known as weld repair and metal deposition. The interest in the CWM approach applied to AM has increased considerably, and there are new challenges in this context regarding welding. The current state and need for developments from the perspective of the authors are summarised in this study.
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| 3. |
- Cirillo, Emilio N.M., et al.
(författare)
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Does communication enhance pedestrians transport in the dark?
- 2016
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Ingår i: Comptes rendus. Mecanique. - : Elsevier. - 1631-0721 .- 1873-7234. ; 344:1, s. 19-23
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Tidskriftsartikel (refereegranskat)abstract
- We study the motion of pedestrians through an obscure tunnel where the lack of visibility hides the exits. Using a lattice model, we explore the effects of communication on the effective transport properties of the crowd of pedestrians. More precisely, we study the effect of two thresholds on the structure of the effective nonlinear diffusion coefficient. One threshold models pedestrian communication efficiency in the dark, while the other one describes the tunnel capacity. Essentially, we note that if the evacuees show a maximum trust (leading to a fast communication), they tend to quickly find the exit and hence the collective action tends to prevent the occurrence of disasters.
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| 4. |
- Lindgren, Lars-Erik, et al.
(författare)
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Towards predictive simulations of machining
- 2016
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Ingår i: Comptes rendus. Mecanique. - : Elsevier BV. - 1631-0721 .- 1873-7234. ; 344:4-5, s. 284-295
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Tidskriftsartikel (refereegranskat)abstract
- Machining simulations are challenging with respect to both numerical issues and physical phenomena occurring during machining. The latter are mainly related to the description of the bulk material behaviour (plasticity) and surface properties (friction and wear). The aim of this paper is to present what is required for predictive models, depending on their scopes, as well as the needed developments for the future. The paper includes a short review of selected works that are relevant for this purpose as well as conclusions based on our own experience
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| 5. |
- Beaubert, Francois, et al.
(författare)
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Design of a device to induce swirling flow in pipes : A rational approach
- 2015
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Ingår i: Comptes rendus. Mecanique. - : Elsevier BV. - 1631-0721 .- 1873-7234. ; 343:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a rational approach is proposed to design a device for inducing swirling flow in heat exchanger pipes, for improved efficiency in the laminar regime. First, 2D computational fluid dynamics results lead to select, among four profiles, the blade profile with the most favorable lift to drag ratio. Then, the fluid flow in the swirler made with the selected blade profile is simulated in 3D, for Reynolds numbers ranging from 50 to 1600. Based on the simulation results, an analytic approximation of the evolution of the tangential fluid velocity is proposed as a function of the Reynolds number.
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| 6. |
- Biciusca, Tonino, et al.
(författare)
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Simulation of liquid-vapour phase separation on GPUs using Lattice Boltzmann models with off-lattice velocity sets
- 2015
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Ingår i: Comptes rendus. Mecanique. - : ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER. - 1631-0721 .- 1873-7234. ; 343:10-11, s. 580-588
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Tidskriftsartikel (refereegranskat)abstract
- We use a two-dimensional Lattice Boltzmann model to investigate the liquid-vapour phase separation in an isothermal van der Waals fluid. The model is based on the expansion of the distribution function up to the third order in terms of Hermite polynomials. In two dimensions, this model is an off-lattice one and has 16 velocities. The Corner Transport Upwind Scheme is used to evolve the corresponding distribution functions on a square lattice. The resulting code allows one to follow the liquid-vapour phase separation on lattices up to 4096 x 4096 nodes using a Tesla M2090 Graphics Processing Unit. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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| 7. |
- Cirillo, Emilio N. M., et al.
(författare)
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Can cooperation slow down emergency evacuations?
- 2012
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Ingår i: Comptes rendus. Mecanique. - : Elsevier. - 1631-0721 .- 1873-7234. ; 340:9, s. 625-628
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Tidskriftsartikel (refereegranskat)abstract
- We study the motion of pedestrians through obscure corridors where the lack of visibility hides the precise position of the exits. Using a lattice model, we explore the effects of cooperation on the overall exit flux (evacuation rate). More precisely, we study the effect of the buddying threshold (of no–exclusion per site) on the dynamics of the crowd. In some cases, we note that if the evacuees tend to cooperate and act altruistically, then their collective action tends to favor the occurrence of disasters.
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| 8. |
- Koekkoek, Gide, et al.
(författare)
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Stroke plane angle controls leading edge vortex in a bat-inspired flapper
- 2012
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Ingår i: Comptes Rendus. Mecanique. - : Elsevier BV. - 1873-7234 .- 1631-0721. ; 340:1-2, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- The present interest in micro air vehicles has given the research on bat flight a new impulse. With the use of high speed cameras and improved PIV techniques, the kinematics and aerodynamics of bats have been studied in great detail. A robotic flapper makes it possible to do measurements by systematically changing only one parameter at a time and investigate the parameter space outside the natural flight envelope of bats without risking animal safety. For this study, a robotic flapper (RoBat), inspired by Leptonycteris yerbabuenae was developed and tested over the speed range 1-7 m/s, with variable maximum angles of attacks (AoA(max) = 55 degrees and 15 degrees, respectively) and constant AoA(max). = 55 degrees. These measurements show the presence of a leading edge vortex (LEV) for low speeds and a fully attached flow for high speeds at low AoA(max), which is in line with natural bat flight. A LEV occurs for AoA(max) = 55 degrees throughout the complete flight speed range, and throughout which the LEV circulation coefficient remains rather constant. This implies that bats and micro air vehicles could use LEVs for high load maneuvers also at relatively high flight speeds. However, at high flight speeds the LEV bursts, which causes increased drag, most likely due to a decrease in Strouhal number. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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