Characteristics of transition flow between parallel plates

Measurements of pressure drop and mean local fluid velocities have been made in a smooth rectangular duct of large aspect ratio. Data have been taken on the steady, isothermal flow of water at room temperature in the viscous, transition, and lower turbulent ranges of flow. Impact probes were installed in the center of the stream, where flow between infinitely broad parallel plates was closely approximated. The limits of the transition range are discussed, and mean local fluid velocities are correlated. Comparison is made with transitional behavior in smooth tubes.