buoyancy jet;  numerical simulation;  interactive visual calculation;  Visual Fortran;  QuickWin;  Multithreading

In large-scale nonlinear digital models, with the help of interactive visual computing technology, with buoyancy jet numerical simulation as the engineering application background, QuickWin applications are developed in Visual Fortran, using its graphics library to design interface elements and draw graphics, and creating multi-threaded applications as a breakthrough, so that calculations and drawings are carried out in a separate thread in addition to the main thread, and the main thread is specially used to respond to the events generated by the controls in the window. The results show that interactive visual computing technology can be implemented in the Visual Fortran environment.