Introduction of the ASP3D computer program for unsteady aerodynamic and aeroelastic analyses

Original publisher: Hampton, Va. : National Aeronautics and Space Administration, Langley Research Center, [2005] OCLC Number: (OCoLC)643126670 Excerpt: ... The ASP3D Computer Program The ASP theory has been used as the basis for a new computer code called ASP3D ( Advanced Small Perturbation - 3D ), which involves either AF1-or AF2-type approximate factorization algorithms and a FAS ( full approximation scheme ) multigrid procedure for the solution of the ASP potential flow equation and associated boundary conditions. The ASP3D code can treat aircraft configurations involving multiple lifting surfaces with leading and trailing edge control surfaces, and a fuselage. The new code is described here along with conceptual and theoretical comparisons with the CAP-TSD code. The author is in a unique position as the developer of both computer codes to compare, contrast, and ultimately make conclusions regarding the underlying formulations and utility of each code.-Governing Equation The three-dimensional general small perturbation equation may be written in Cartesian coordinates as����f f f f 0 1 2 3 + + + = 0 t x y�z���where the Cartesian fluxes are defined as�f =�A�B��0 t x H 2 3 2 2������f = C + D + E + F + G + 1 x x x y x y 2���H 2 3 f = 1 + H + + F�������2 x x y y�2�f =�3 z with the constants defined as�2 2 2 C = 1 A = M B = 2M D = 1�M����1 1 1 2 2 2 2����E =�+ 1 M F =�+ 1 M G = 3 ) M H =��1 ) M (�( ) ( ) (����2 6 2����Figure 11 shows flux quantities as functions of streamwise velocity ( u = 1 + ) for φ x the ASP theory computed for freestream Mach numbers ranging from M = 0.0 to 1.2. ∞����Figure 11 ( a ) shows the streamwise part of the mass flux f and Figure 11 ( b ) shows the 1 φ derivative of the streamwise part of the mass flux ∂ f / ∂. Figure 11 ( a ) emphasizes that 1 x the ASP mass flux is an asymmetric function about u = 0 ( stagnation ) and the M = 0.0 ∞ result is a line with a slope of unity. If desired the positive offset in f can be removed by 1 repl...