Abstract: An essential component of a finite volume method (FVM) is the advection scheme that estimates values on the cell faces based on the calculated values on the nodes or cell centers. The most widely used advection schemes are upwind schemes. These schemes have been developed in FVM on different kinds of structured and unstructured grids. In this research, the physical influence scheme (PIS) is developed for a cell-centered FVM that uses an implicit coupled solver. Results are compared with the exponential differencing scheme (EDS) and the skew upwind differencing scheme (SUDS). Accuracy of these schemes is evaluated for a lid-driven cavity flow at Re = 1000, 3200, and 5000 and a backward-facing step flow at Re = 800. Simulations show considerable differences between the results of EDS scheme with benchmarks, especially for the lid-driven cavity flow at high Reynolds numbers. These differences occur due to false diffusion. Comparing SUDS and PIS schemes shows relatively close results for the backward-facing step flow and different results in lid-driven cavity flow. The poor results of SUDS in the lid-driven cavity flow can be related to its lack of sensitivity to the pressure difference between cell face and upwind points, which is critical for the prediction of such vortex dominant flows.
Abstract: The design requirements for successful human
accommodation in urban spaces are well known; and the range of
facilities available for meeting urban water quality and quantity
requirements is also well established. Their competing requirements
must be reconciled in order for urban spaces to be successful for
both. This paper outlines the separate human and water imperatives
and their interactions in urban spaces. Stormwater management
facilities- relative potential contributions to urban spaces are
contrasted, and design choices for achieving those potentials are
described. This study uses human success of urban space as the
evaluative criterion of stormwater amenity: human values call on
stormwater facilities to contribute to successful human spaces.
Placing water-s contribution under the overall idea of successful
urban space is an evolution from previous subjective evaluations.
The information is based on photographs and notes from
approximately 1,000 stormwater facilities and urban sites collected
during the last 35 years in North America and overseas, and the
author-s experience on multi-disciplinary design teams. This
conceptual study combines the disciplinary roles of engineering,
landscape architecture, and sociology in effecting successful urban
design.