PDAS home > Contents > Panair
Public Domain Aeronautical Software (PDAS)

PANAIR (an abbreviation for "panel aerodynamics") is a state-of-the art computer program developed to predict inviscid subsonic and supersonic flows about an arbitrary configuration by means of a higher order panel method. Generally speaking, a panel method solves a linear partial differential equation numerically by approximating the configuration surface by a set of panels on which unknown "singularity strengths" are defined, imposing boundary conditions at a discrete set of points, and thereby generating a system of linear equations relating the unknown singularity strengths. These equations are solved for the singularity strengths which provide information on the properties of the flow. PANAIR differs from earlier panel methods by employing a "higher order" panel method; that is, the singularity strengths are not constant on each panel. This is necessitated by the more stringent requirements of supersonic problem. The potential for numerical error is greatly reduced in the PANAIR program by requiring the singularity strength to be continuous. It is also this "higher order" attribute which allows PANAIR to be used to analyze flow about arbitrary configurations. PANAIR can handle the simple configurations considered in the preliminary design phase and later serve as the "analytical wind tunnel" which can analyze the flow about the final detailed, complex configurations.

PANAIR includes the following capabilities:

• the ability to handle, within the limitations of linear potential flow theory, completely arbitrary configurations, using either exact or linearized boundary conditions;
• the ability to handle asymmetric configurations as well as those with one or two planes of symmetry;
• the ability to handle symmetric configurations in either symmetric or asymmetric flow;
• the ability to calculate pressures, forces, and moments using a variety of pressure formulas (such as isentropic, linear, etc.), including the forces and moments due to flow through the surface;

Most problems can be modeled with a minimum of user input. In general, the aircraft surface is partitioned into several networks of surface grid points, such as a forebody network, a wing network, and so forth. The coordinates of the input grid points must be computed and entered by the user; PANAIR does not generate grid point coordinates. PANAIR connects the grid points in each network with piecewise flat panels. The user also supplies information concerning the free-stream onset flow, the angle of attack, and the angle of sideslip. Numerous flow quantities are computed at points on the vehicle surface and at points in space. These include pressure coefficients, total and perturbation values of velocity and mass flux components, total and perturbation potential, local Mach number, and vacuum pressure coefficient. The pressure coefficients on individual panels are fitted with two dimensional quadratic splines and integrated to obtain the six components of force and the moment coefficients. These coefficients may be output for each panel, for columns of panels, for each network, or for any combination of networks.

This program was released by NASA through COSMIC as ARC-11398. The italicized text above is from the official NASA release.

PDAS home > Contents > Panair
Public Domain Aeronautical Software (PDAS)