Investigation of Turbulence Effect on Dynamic Behaviour of Aircraft Through Use of JDYNASIM: A Platform Independent Simulation Software

Abstract

The need of fast and interactive tool to simulate aircraft behaviour is a demand of modern technology. This necessity is more evident when light aircraft and sailplanes are involved.. This paper presents an attempt to give simulation possibility almost to everyone through the use of JDynaSim code, written to meet this goal. JDynaSim is an interactive graphic flight simulation code written in JAVA and VRML languages which practically allows everyone to fly the aeroplane under investigation. This is true due to the fact that JAVA is a language born to work under a generic Internet browser (such as Microsoft Explorer or Netscape) and thus it is independent from the operating system under which it is running. Dynamic motion equations are solved by 12 ordinary non-linear differential equations in which the non-linear forces are input in multidimensional matrix form and are interpolated at each time instant. Advancing in time is performed using a 4th order Runge-Kutta integration scheme. Translation equations of motion are written in a flight path axis system while rotational equations are written on body axis system. An on-purpose written pre-processor has to be used to transform forces to appropriate reference system. The code can interactively read mouse and keyboard inputs as well as files with command laws assigned in function of time. There is the possibility to record the interactive session performed and then to repeat the manoeuvre. This paper presents also the code extension for simulating the effect of gusts generated according to classical theories. In particular investigation has been performed to compare results coming from classical theories on aircraft responses to gusts inputs respect to those coming from JDynSim flight simulator. JDynaSim is available to everybody through Internet at the following URL: http://www.dpa.unina.it/coiro/