A hybrid field panel/finite difference method for 3-D potential unsteady transonic flow calculations

Application of NLR's calculation methods to transonic flow about oscillating wings

“…2,FTRAN3 has not changed significantly. The code still solves the time-linearized full potential equation with small-disturbance boundary conditions and pressure representations.…”

“…In Ref. 2, calculations with FTRAN3 were discussed in which mainly a coarse idealization of the mean steady flowfield was used, approximated from measured data. The purpose of the present paper is to demonstrate the potentialities of FTRAN3 by showing results of calculations for several planforms in transonic flow where the mean steady flowfields have been determined by application of the XFLO22 code.…”

Current status of computational methods for transonic unsteady aerodynamics and aeroelastic applications

“…Computed unsteady pressure distributions documentedthe utilityof s-plane Padecurve fits of transonicairare given for several wing configurations,including wings with loads (whichrely on the conceptsof linearityand superposition) oscillating control surfaces, for aeroelastic analysis. Viscous effects are shownto generally result in larger values of flutter speedsince transonic effects are Hounjet [74] describes a hybridfield-panel/finite-difference alleviated by the boundary layer. Zimmerman[170] describes procedure (FTRAN3) which combines features of both linear the applicationof severalunsteady aerodynamictheories to the and nonlinear methods.…”

“…At each time step, the formulations or derived from experimentaldata. Hounjet [74] new location of the body boundaryobtained fromthe aeroelastic is representative of this approach to unsteady transonic flow equationsof motion is used to solve for the new static equilibmodeling, rium locationof the nodesof the springnetwork. Robinsonet al…”

“…ibility effects are greatest, is modeled using volume sources. Vossalso describes a combinedfield-panel/finite-difference proAt the NLR, a numberof unsteady aerodynamiccomputacedure, tional procedureshave been developed for use in transonic flutter prediction (Hounjet [74] and Steiginga and Houwink [149]). Zimmerman and Vogel [169] describe a time-linearized Zwann [168] describes an investigation into the accuracy of method for solving the transonic small perturbation equation several of these methods for predicting flutter of a transport-(LIN TSP).…”