SUMMARY An implicit meshless scheme is developed for solving the Euler equations, as well as the laminar and Reynolds‐averaged Navier–Stokes equations. Spatial derivatives are approximated using a least squares method on clouds of points. The system of equations is linearised, and solved implicitly using approximate, analytical Jacobian matrices and a preconditioned Krylov subspace iterative method. The details of the spatial discretisation, linear solver and construction of the Jacobian matrix are discussed; and results that demonstrate the performance of the scheme are presented for steady and unsteady two dimensional fluid flows. Copyright © 2012 John Wiley & Sons, Ltd.

Meshless methods are attractive for simulating moving body problems. The selection of the stencils over the domain for the meshless solver is crucial for the method to be competitive with established computational fluid dynamics techniques. Stencil selection is relatively straightforward if the point distributions are isotropic in nature, however, this is rarely the case in computations that solve the Navier-Stokes equations. In this paper, a fully automatic method of selecting the stencils from anisotropic point distributions, which are obtained from overlapping structured grids, is outlined. The original connectivity and the concept of a resolving direction are used to help construct good quality stencils with limited user input.

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The ability of computational fluid dynamics to predict the steady and unsteady fluid flow over a generic UCAV configuration, with and without control surface deflections, at off design conditions is investigated. The complex, non-linear flow, various combinations of control surface deflection and the presence of multiple interacting vortices on the flow histories provides a challenging test for current capability. A range of static and dynamic test cases have been computed, for both low and high speed flows, for comparison with experimental data, obtained as part of the NATO STO AVT-201 Task Group. The simulations are performed using a multiblock code to solve the Reynolds-Averaged Navier-Stokes equations; and the control surfaces are modelled with a deformed mesh and blended gaps that simplify the geometry. These tests will provide an assessment of the ability of computational fluid dynamics to evaluate such flows, and will allow for deficiencies in the state of the art to be identified.