MULTIPOINT INVERSE DESIGN OF AN INFINITE CASCADE OF AIRFOILS

This paper describes a method for the design of an infinite cascade in incompressible flow. The method is based on conformal mapping and doe s allow for multipoint design. The cascade blade to be determined is d ivided into a desired number of segments. Over each segment, the veloc ity distribution is prescribed together with an inlet or outlet flow a ngle at which this velocity distribution is to be achieved. In this wa y multipoint design requirements can be met. It is necessary to satisf y several conditions that arise to guarantee compatibility with the in let and outlet flow as well as closure of the cascade blade. Satisfact ion of these conditions does not necessarily result in a cascade with all of the desired characteristics. For example, the cascade blades ma y be bulbous or crossed. Through Newton iteration, however, the desire d characteristics may be prescribed directly. Four examples will be il lustrated to demonstrate the capability of the method.