1. formulation eliminates the need for computing the grid motion a t each time step. For these type of problems, once the grid i s generated i n the moving frame o f reference it remains constant since it i s rigidly fixed i n the moving frame. The authors of this paper have developed this formulation and presented computational applications to pitching oscillation of airfoils, rolling oscillation of delta wings for locally conical flows and pitching oscillation of delta wings for threedimensional flows i n Refs. 1-6.
2. Astronautics, Inc., 1989. All rights reserved. motion. The literature shows a few methods to deal with this problem that are based on crude grid interpolation or on static or dynami? equilibrium of elastic trusses. Ide and Shankar compute the grid speed on the body solid boundary and define the grid speed for each field-grid point such that the grid speed values a t the outer boundary go to zero. Using this interpolation scheme, the new grid locations and metrics are computed.
3. I n Eqs. (1)-(18) the indical notation i s used for convenience. Hence the indices k, k, n are summation indices and m i s a free index. The range o f k, i , m and n i s 1-3 and ak .< Lagrangian Description of the Linearized Navier-Displacement Equations
4. '7 imp 1i c it dissipation operator, A; the invscidflux Jacobian, Hn the source -term Jacobian and (Av): the VI scous-f 1ux Jacobian. The vector i ( i n ) i s the spatial-difference vector of the inviscid-flux vectors, viscous flux-vector, source vector and explicit-dissipation vector. Details of the computational scheme are given i n Refs. 3-6. The local conical flow solution i s obtained from Eq. (30) by applying the equation to three planes and equating the absolute conservative components of the flow vector f i e l d on these planes.