From Hunter Research and Technology:
Flow is a handy fluid dynamics app for the iPhone and iPod Touch. The software implements 1D compressible flow equations, normal and oblique shock relations, laminar and turbulent flat plate boundary layer development, standard atmospehere modeling, and the gas properties of air at sea level. Standard atmosphere and air properties calculations offer a choice of US or metric units, which is saved as a default.
Flow is a great tool for aerospace engineers, mechanical engineers, students, and anyone else working in fluid dynamics.
Please visit the Flow website for technical details and more info.