The Numerical Wind Tunnel (NWT) is a distributed memory parallel computer for research and development in numerical simulation. Effective utilization is a major consideration in the design of the NWT system. User interfaces in NWT were produced in the same manner as in the existing system (Fujitsu FACOM VP-2100), comprising shell-scripts (NS-Shell) and command procedures (NS-Command). Numerous job-processing functions were included, resulting in a system that may be used easily and with confidence and delivering high overall performance. Experiments confirmed that all goals for system effectiveness were achieved. In this paper concepts and detailed functions of system design for NWT jobs are presented, along with their availability.