A run-time visualization and solution-steering tool, TPview, has been developed to overcome difficulties commonly encountered with large-scale numerical simulations on high-performance parallel computer systems. TPview provides the interface between the parallel computer system and the visualization software running on a remote workstation, During the computation cycle, data distributed across multiple processors are periodically sent via sockets to the workstation for rendering., In addition, internal parameters of the simulation code can be modified using a user-defined graphical interface, enabling remote guiding of the solution procedure, It is shown that such a run-time visualization and solution-steering tool can be implemented with minimal effort from the programmer and end user. Examples are presented of the use of TPview in conjunction with a parallel multiblock flow solver and a commercial visualization package. These examples demonstrate its ability to provide greater insights for the analysis of complex flow simulations. (C) 1998 American Institute of Physics.