Water, Wastewater & Stormwater
395236 - Tracer Analysis in Steady and Unsteady Reynolds-averaged Navier-Stokes simulations of the Flow in an Oxidation Ditch
Tuesday, June 5
2:00 PM - 3:30 PM
Location: Greenway EF
Andres Tejada-Martinez, Tampa, FL – University of South Florida; Jie Zhang, Seattle, WA – Carollo Engineers, Inc; Aydin Sunol, Tampa, FL – University of South Florida
Passive tracer analysis is a commonly used method to evaluate the hydraulic performance of environmental and chemical engineering fluid systems. By adding a non-reactive chemical/particle into the system and observing the change in the concentration of the chemical/particle at the effluent, the hydraulic performance of the system can be evaluated. Unsteady flow conditions have a significant impact on tracer transport, especially in wastewater treatment facilities which have relatively long residence time and are subject to unsteady flow conditions induced by operational requirements. However, for the purpose of reducing computational expense, numerical tracer analysis is commonly performed under the steady flow assumption, thereby precluding potentially important unsteady flow effects. Tracer analysis using computational fluid dynamics based on the Reynolds-averaged Navier-Stokes (RANS) equations is performed for a full-scale oxidation ditch under unsteady and steady state conditions. Unsteady flow conditions are generated through dynamic inflow and variable speeds of the surface aerators driving the flow in the ditch, characterizing normal operating conditions. The commonly used assumption of steady flow for tracer analysis will be assessed based on the RANS simulation results.