The bulk properties of materials in an extreme environment such as high temperature and high pressure can be understood by studying anharmonic effects due to the vibration of lattice ions and thermally excited electro...The bulk properties of materials in an extreme environment such as high temperature and high pressure can be understood by studying anharmonic effects due to the vibration of lattice ions and thermally excited electrons.In this spirit,in the present paper,anharmonic effects are studied by using the recently proposed mean-field potential（MFP） approach and Mermin functional which arise due to the vibration of lattice ions and thermally excited electrons,respectively.The MFP experienced by a wanderer atom in the presence of surrounding atoms is constructed in terms of cold energy using the local form of the pseudopotential.We have calculated the temperature variation of several thermophysical properties in an extreme environment up to melting temperature.The results of our calculations are in excellent agreement with the experimental findings as well as the theoretical results obtained by using first principle methods.We conclude that presently used conjunction scheme（MFP＋pseudo potential） is simple computationally,transparent physically,and accurate in the sense that the results generated are comparable and sometimes better than the results obtained by first principle methods.Local pseudopotential used is transferable to extreme environment without adjusting its parameters.展开更多
Experiments and computations were performed over an ogive-cylinder body having an lift-to-drag ratio of 16 at a diameter Reynolds number of 29000. The side force on the slender body augments with increasing angles of ...Experiments and computations were performed over an ogive-cylinder body having an lift-to-drag ratio of 16 at a diameter Reynolds number of 29000. The side force on the slender body augments with increasing angles of attack for the case without a ring. This increase was mainly due to the increase in the asymmetry of the existing vortex pair in the wake of the body. Attempts were made to completely reduce the existing side force at the angle of attack ranging from 35° to 45°.Three rectangular cross-sectioned circumferential rings having a height of 3% of the local diameter were placed at axial distances of 2.5, 3.5 and 4.5 times the base diameter from the tip of the body so as to reduce the side force. The results obtained indicate that inclusion of three rings completely alleviated the side force on the slender body at the angle of attack ranging from 0° to 45°. The presence of rings was found to alter the growth of the vortices that helped in the reduction of the side force. Computations performed were in reasonable agreement with the experiments.展开更多
基金Project supported by the Department of Science and Technology-Fund for Improvement of Science and Technology Infrastructure Project(DST-FIST)(Level 1)of Department of Sciences and Technology(DST),New Delhi(Grant No.SR/FST/PST-001/2006)
文摘The bulk properties of materials in an extreme environment such as high temperature and high pressure can be understood by studying anharmonic effects due to the vibration of lattice ions and thermally excited electrons.In this spirit,in the present paper,anharmonic effects are studied by using the recently proposed mean-field potential（MFP） approach and Mermin functional which arise due to the vibration of lattice ions and thermally excited electrons,respectively.The MFP experienced by a wanderer atom in the presence of surrounding atoms is constructed in terms of cold energy using the local form of the pseudopotential.We have calculated the temperature variation of several thermophysical properties in an extreme environment up to melting temperature.The results of our calculations are in excellent agreement with the experimental findings as well as the theoretical results obtained by using first principle methods.We conclude that presently used conjunction scheme（MFP＋pseudo potential） is simple computationally,transparent physically,and accurate in the sense that the results generated are comparable and sometimes better than the results obtained by first principle methods.Local pseudopotential used is transferable to extreme environment without adjusting its parameters.
文摘Experiments and computations were performed over an ogive-cylinder body having an lift-to-drag ratio of 16 at a diameter Reynolds number of 29000. The side force on the slender body augments with increasing angles of attack for the case without a ring. This increase was mainly due to the increase in the asymmetry of the existing vortex pair in the wake of the body. Attempts were made to completely reduce the existing side force at the angle of attack ranging from 35° to 45°.Three rectangular cross-sectioned circumferential rings having a height of 3% of the local diameter were placed at axial distances of 2.5, 3.5 and 4.5 times the base diameter from the tip of the body so as to reduce the side force. The results obtained indicate that inclusion of three rings completely alleviated the side force on the slender body at the angle of attack ranging from 0° to 45°. The presence of rings was found to alter the growth of the vortices that helped in the reduction of the side force. Computations performed were in reasonable agreement with the experiments.
