Implicit scheme for meshless compressible Euler solver

In this paper, an implicit scheme is presented for a meshless compressible Euler solver based on the Least Square Kinetic Upwind Method (LSKUM). The Jameson and Yoon’s split flux Jacobians formulation is very popular in finite volume methodology, which leads to a scalar diagonal dominant matrix for an efficient implicit procedure (Jameson & Yoon, 1987). However, this approach leads to a block diagonal matrix when applied to the LSKUM meshless method. The above split flux Jacobian formulation, along with a matrix-free approach, has been adopted to obtain a diagonally dominant, robust and cheap implicit time integration scheme. The efficacy of the scheme is demonstrated by computing 2D flow past a NACA 0012 airfoil under subsonic, transonic and supersonic flow conditions. The results obtained are compared with available experiments and other reliable computational fluid dynamics (CFD) results. The present implicit formulation shows good convergence acceleration over the RK4 explicit procedure. Further, the accuracy and robustness of the scheme in 3D is demonstrated by computing the flow past an ONERA M6 wing and a clipped delta wing with aileron deflection. The computed results show good agreement with wind tunnel experiments and other CFD computations

Magnetic phase diagrams of the Kagome staircase compounds Co3V2O8 and Ni3V2O8

An extensive low temperature magnetization study of high quality single crystals of the Kagome staircase compounds Ni3V2O8 and Co3V2O8 has been performed, and the H - T phase diagrams have been determined from these measurements. The magnetization and susceptibility curves for Co3V2O8 are analysed in terms of their compatibility with the different ferromagnetic and antiferromagnetic structures proposed for this compound. For Ni3V2O8, the phase diagram is extended to magnetic fields higher than previously reported; for a field applied along the a axis, the low temperature incommensurate phase is found to close at around 90 kOe