Rotorwash Computer Model (User's Guide)

Abstract : The user's guide for the Rotorwash (ROTWASH) Analysis program is documented in this report. This computer program is used to analyze the rotorwash flow field characteristics and their effect on the environment for rotorcraft in hovering and low speed flight in close proximity to the ground. The documentation provides step-by-step descriptions on the use of each analysis option and a listing of the IBM PC/PC-compatible based FORTRAN-77 software. A brief introductory section to the report describes the history of the ROTWASH analysis software. References for the mathematical models used in the analysis modules are included in the report. A companion report entitled Evaluation of Rotorwash Characteristics for Tiltrotor and Tiltwing Aircraft in Hovering Flight, DOT/FAA/RD-90/16, evaluates rotorwash characteristics of 11 different types of tiltrotor and tiltwing aircraft for comparison purposes. Flight test data, as correlated with analysis tools, are presented for the XV-1 5 tiltrotor and CL-84 tiltwing. A second companion report, entitled Analysis of Rotorwash Mishaps, DOT/FAA/RD-90/17, uses the ROTWASH program to analyze rotorwash induced mishaps in an effort to determine threshold levels at which rotorwash presents a potential hazard.