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51.
A sharp‐interface immersed boundary framework for simulations of high‐speed inviscid compressible flows
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Shuvayan Brahmachary Ganesh Natarajan Vinayak Kulkarni Niranjan Sahoo 《国际流体数值方法杂志》2018,86(12):770-791
A new finite‐volume flow solver based on the hybrid Cartesian immersed boundary (IB) framework is developed for the solution of high‐speed inviscid compressible flows. The IB method adopts a sharp‐interface approach, wherein the boundary conditions are enforced on the body geometry itself. A key component of the present solver is a novel reconstruction approach, in conjunction with inverse distance weighting, to compute the solutions in the vicinity of the solid‐fluid interface. We show that proposed reconstruction leads to second‐order spatial accuracy while also ensuring that the discrete conservation errors diminish linearly with grid refinement. Investigations of supersonic and hypersonic inviscid flows over different geometries are carried out for an extensive validation of the proposed flow solver. Studies on cylinder lift‐off and shape optimisation in supersonic flows further demonstrate the efficacy of the flow solver for computations with moving and shape‐changing geometries. These studies conclusively highlight the capability of the proposed IB methodology as a promising alternative for robust and accurate computations of compressible fluid flows on nonconformal Cartesian meshes. 相似文献
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Shekhar Kumar U. Kamachi Mudali R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):587-589
Tri-n-butyl phosphate (TBP) is the workhorse of solvent extraction operations in nuclear fuel cycle as well as an important industrial chemical. Its PVT properties are not available in literature. In this study, PVT properties of TBP, estimated using group contribution method, are reported. Wagner constants were also reported in the range of 273.15?K to critical temperature. 相似文献
55.
G. Muthusamy P. Viswanathamurthi M. Muthukumar K. Natarajan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):2115-2124
Several new hexa-coordinated ruthenium(II) and penta-coordinated rhodium(I) complexes of the types [RuCl(CO)(PPh 3 ) 2 (TSC)], [RuH(CO)(PPh 3 ) 2 (TSC)], and [Rh(PPh 3 ) 3 (TSC)] (where TSC = anion of thiosemicarbazone Schiff bases) have been prepared by the reactions of [RuHCl(CO)(PPh 3 ) 3 ], [RuH 2 (CO)(PPh 3 ) 3 )], and [RhH(PPh 3 ) 4 ] with thiosemicarbazones of 2-furaldehyde (H-FTSC), thiophene-2-carboxaldehyde (H-TCTSC), p-anisaldehyde (H-ATSC), piperonaldehyde (H-PTSC), and cyclohexanone (H-CTSC). All the new complexes obtained have been characterized on the basis of elemental analysis, IR, 1 H NMR, 31 P NMR, and electronic spectral data. 相似文献
56.
P. Natarajan 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10-11):1285-1306
Thiazine and phenazine dyes are known to exhibit photoredox behavior in the excited states of these molecules. These dyes are covalently attached to macromolecules, and the photochemistry has been investigated in homogeneous solution and as thin films coated onto electrodes. Flash photolysis of the macromolecular thionine in the presence of quenchers shows reduction of the dye and the subsequent disproportionation of the reduced dye. In the case of macromolecular thionine, evidence for the formation of a complex between ferrous ion and thionine is observed in the flash photolysis experiments. Photoelectrochemical studies show a new type of behavior for the macromolecular dye films coated onto electrodes. Macromolecular thionine film coated onto platinum electrode makes the electrode a cathode on illumination of the electrode. Macromolecular phenosafranine dye films coated onto electrodes change the polarity of the illuminated electrode depending upon the nature of the macromolecule. 相似文献
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Prasannan Karthika Dr. Natarajan Rajalakshmi Dr. Kaveripatnam S. Dhathathreyan 《Chemphyschem》2013,14(16):3822-3826
A low-cost polyester cellulose paper has been used as a substrate for a flexible supercapacitor device that contains aqueous carbon nanotube ink as the electrodes and a polyvinyl alcohol (PVA)-based gel as the electrolyte. Gel electrolytes have attracted much interest due to their solvent-holding capacity and good film-forming capability. The electrodes are characterized for their conductivity and morphology. Because of its high conductivity, the conductive paper is studied in supercapacitor applications as active electrodes and as separators after coating with polyvinylidene fluoride. Carbon nanotubes deposited on porous paper are more accessible to ions in the electrolyte than those on flat substrates, which results in higher power density. A simple fabrication process is achieved and paper supercapacitors are tested for their performance in both aqueous and PVA gel electrolytes by using galvanostatic and cyclic voltammetry methods. A high specific capacitance of 270 F g−1 and an energy density value of 37 W h kg−1 are achieved for devices with PVA gel electrolytes. Furthermore, this device can maintain excellent specific capacitance even under high currents. This is also confirmed by another counter experiment with aqueous sulfuric acid as the electrolyte. The cycle life, one of the most critical parameters in supercapacitor operations, is found to be excellent (6000 cycles) and less than 0.5 % capacitance loss is observed. Moreover, the supercapacitor device is flexible and even after twisting does not show any cracks or evidence of breakage, and shows almost the same specific capacitance of 267 F g−1and energy density of 37 W h kg−1. This work suggests that a paper substrate can be a highly scalable and low-cost solution for high-performance supercapacitors. 相似文献
58.
Parthasarathy Saravanan Suparna Gupta Arpita DattaGupta Sonia Gupta Vinod K. Singh 《合成通讯》2013,43(15):2695-2699
The cleavage of α-hydroxy tert-butyldimethylsilyl ether to diol takes place efficiently with LAH. It has been proposed that the reaction proceeds via intramolecular hydride transfer from the alkoxy aluminium hydride. In order to substantiate this, reduction of TBDMS ether with LAH in a variety of substrates was studied. 相似文献
59.
Abstract A new and practical synthesis of montelukast sodium, an antiasthmatic drug, is described. The key steps are the synthesis of nitrile derivative 4 by chiral reduction of keto ester 9 using (?)-DIP-Cl, synthesis of vinylquinoline framework 16 by Wittig reaction, and Heck coupling of nitrile 4 with vinylquinoline 16. The method is operationally simple and suitable for the industrial production of the drug substance. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
60.
Thangavel Saravanan 《合成通讯》2013,43(16):2350-2358
An efficient one-pot synthesis of α -hydroxy propargylic esters by chemoselective reduction followed by transesterification using NaBH4 in combination with CeCl3 · 7H2O is described.