Dimensionless Area Research Articles

A Unit Hydrograph Concept for Predicting Flood Hydrographs from Suburban Subdivisions

ABSTRACT EVIDENCE abounds in hydrologic literature that urbanization increases direct runoff. This runoff problem has been routinely combated with so-called corrective measures which are oftentimes uncoor-dinated and collectively ineffective. This paper proposed the integration of judicious land use planning and im-proved urban storm drainage design as an effective measure against the urban flood problem. To that effect, a dimensionless unit area hydrograph is derived. It is then demonstrated how this hydrograph can be used by land use planners to predict the hydrologic effects of pro-posed land use designs and by design engineers to quan-tify runoff. The technique uses a minimum of data, re-quires no field measurements, and is easy to apply.

Capillary Flow in Triangular Grooves

Solutions to the two-dimensional equations of motion for steady laminar flow in grooves are obtained by the Galerkin boundary method. The two independent parameters which characterize the flow configuration are the half angle of the liquid-filled triangular groove and the contact angle of the shear-free meniscus. The analytical results include dimensionless velocity contours, average velocity, hydraulic diameter, and area. The friction factor coefficient K, where f = K/Re and Re is Reynolds number based upon hydraulic diameter, is also found. Results are reported for channel half angles from 5–60 deg and contact angles from 0.1 deg to the complementary angle (full groove condition). Comparisons with analysis and experimental data for the full groove are made and found to be excellent.