Namrata Karmakar - Academia.edu (original) (raw)
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Vishvesvaraya Technological University, Belgaum, Karnataka, INDIA
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Papers by Namrata Karmakar
Inviscid supersonic flow problems pertaining to weak and strong shocks are computed by first orde... more Inviscid supersonic flow problems pertaining to weak and strong shocks are computed by first order van Leer's flux vector splitting (FVS) scheme and Jaisankar and Raghurama Rao's Diffusion-Regulated Local Lax-Friedrichs (DRLLF) scheme. The governing equations are solved through an in-house solver based on the finite volume method (FVM). The performance of the different schemes is analyzed on the basis of various aspects like resolution of computed flow-field, rate of convergence and numerical diffusion. The DRLLF scheme is found to produce the best resolution of the weak shocks. For capturing strong shocks, the van Leer's FVS performs better in terms of shock resolution. A study of the CPU-time for the two schemes to solve the test problems is presented and the algorithmic simplicity of the DRLLF scheme is demonstrated.
The laser stereophotolithography is a process which allows the manufacture of 3D parts by a light... more The laser stereophotolithography is a process which allows the manufacture of 3D parts by a light-induced space-resolved polymerization. In view to obtain microparts, it is necessary on one hand to reduce the polymerization depth and on the other hand the polymerization width in the x-y plane. The addition of an unreactive highly absorbing chemical succeeded in a significant reduction of the polymerization depth (8 to 10 times thinner). We studied the influences of the light flux, of the initiator and the absorbing unreactive chemical concentrations. The experimental data are in good agreement with the theoretical model. The narrowing of the width is disappointing except with one resin. These results nevertheless led us to set up a new apparatus to reduce the beam diameter by a factor of ten. Despite the increase of the light flux, some of the first results are promising.
Inviscid supersonic flow problems pertaining to weak and strong shocks are computed by first orde... more Inviscid supersonic flow problems pertaining to weak and strong shocks are computed by first order van Leer's flux vector splitting (FVS) scheme and Jaisankar and Raghurama Rao's Diffusion-Regulated Local Lax-Friedrichs (DRLLF) scheme. The governing equations are solved through an in-house solver based on the finite volume method (FVM). The performance of the different schemes is analyzed on the basis of various aspects like resolution of computed flow-field, rate of convergence and numerical diffusion. The DRLLF scheme is found to produce the best resolution of the weak shocks. For capturing strong shocks, the van Leer's FVS performs better in terms of shock resolution. A study of the CPU-time for the two schemes to solve the test problems is presented and the algorithmic simplicity of the DRLLF scheme is demonstrated.
The laser stereophotolithography is a process which allows the manufacture of 3D parts by a light... more The laser stereophotolithography is a process which allows the manufacture of 3D parts by a light-induced space-resolved polymerization. In view to obtain microparts, it is necessary on one hand to reduce the polymerization depth and on the other hand the polymerization width in the x-y plane. The addition of an unreactive highly absorbing chemical succeeded in a significant reduction of the polymerization depth (8 to 10 times thinner). We studied the influences of the light flux, of the initiator and the absorbing unreactive chemical concentrations. The experimental data are in good agreement with the theoretical model. The narrowing of the width is disappointing except with one resin. These results nevertheless led us to set up a new apparatus to reduce the beam diameter by a factor of ten. Despite the increase of the light flux, some of the first results are promising.