ASCE has honored Byron Guerrero; Martin F. Lambert, A.M.ASCE; and Rey Chin for the 2024 Karl Emil Hilgard Hydraulic Prize for the paper “Extension of the 1D Unsteady Friction Model for Rapidly Accelerating and Decelerating Turbulent Pipe Flows,” published in the June 2022 issue of Journal of Hydraulic Engineering.
Since the remarkable experimental work by Nikuradse (1933) for steady-state pipe flows, flow resistance in pipes (and by extension open channels) has been addressed with the help of resistance formulas and empirically determined coefficients. Together with the Moody/Rouse chart, this evidence has dominated the design of pipes around the world since the early 1930s of last century. This paper examines the condition of flow unsteadiness in pipes with the use of sophisticated computations coming from direct numerical simulations (DNS). The research provides a detailed assessment of the similarities and differences between these two flow situations with particular emphasis on the shear stress. Results coming from this effort have direct implications on the understanding of time dependence on this basic flow, as well as pave the way to improving current formulations of flow resistance for unsteady situations.
The Karl Emil Hilgard Hydraulic Prize is presented to the author or authors of the paper that is judged to be of superior merit in dealing with a problem of flowing water, either in theory or in practice.
