Multidisciplinary Simulation of a Generic Delta Wing: Aerodynamic, Flight-Dynamic and Structure-Mechanic Coupling

Abstract

The main objective of the DLR project SikMa ("Simulation komplexer Manöver" - Simulation of Complex Maneuvers) is the development and validation of a simulation tool designed for the accurate simulation of a maneuvering, elastic aircraft. The simulation tool combines the coupling of flight-dynamics, aerodynamics, and structure mechanics within a common simulation environment. The numerical codes for each discipline have been developed independently of one another at the various institutes of the DLR. Since these codes should continue to be independent within the simulation environment, a loose coupling approach is required. The simulation environment will be designed so that the discipline-specific codes can be executed on architectures for which they have been optimized. Such a distributed computing approach requires a network-capable interface between the codes. In order to rapidly prototype the communication logic needed for the coupling interfaces, the flight-dynamics and structure-mechanics codes replaced by Python scripts, before the codes are integrated into the end-user simulation environment. A Pyton wrapper interface already exists for the aerodynamics code, which means that extending the code for coupled simulation capabilities is relatively straightforward. The Python-based simulation environment consists of a manager module which sends workflow information and requests for data to the top-level Python-wrappers of the application codes. The communication between the applications is based on a TCP/IP socket approach, where the information flow is tunneled through a SSH connection. Where file transfer is required, the secure-copy protocol is used. Using the Python-coded implementation a loosely coupled simulation of a freely-rotating delta wing configuration, mounted on an elastic sting, has been realized. The simulation was distributed on three separate hardware systems. The success of this simulation will assist with the implementation of the simulation workflow within a more graphically oriented end-user simulation environment.