EXPERIMENTAL ANALYSIS OF THE MORPHODYNAMICS OF CONDUIT FLOW

Wakulla Springs, located in the Woodville Karst Plain (WKP) of Florida’s Big Bend, is a complex phreatic cave system characterized by convoluted shapes and irregular geometry—reaching depths between 45m-90m (Werner, 2001). The depth and expanse of the underground conduit system makes volumetric flow in this region a challenging phenomenon to interpret. However, despite the challenges Wakulla presents to researchers, it poses as a unique system for study in that at least 37 miles of the system have been mapped to date—providing an extensive amount of well documented information about the conduits that is unavailable in other systems (Xu et al., 2015). Wakulla demonstrates distinct flashy spring characteristics, where there is temporarily high volume discharge in the springs. The dynamic nature of a flashy spring is of interest because of their inherent complex flow behavior compared to that of a static spring. Early studies by Darcy (1865), Nikuradse (1933), Colebrook (1939), and Moody (1944) provide a valuable phenomenological equations for flow behavior in pipe systems where the relative roughness (e/D) is minimal.

However, their studies lack detailed data pertaining to flow where the relative roughness is >5 percent, which is common in natural karst conduit systems like Wakulla (Kandlikar et al., 2006). This study will help to quantify the Darcy-Weisbach pipe-flow equation for use in natural systems with high degrees of wall roughness and evaluate the effect of major and minor loss parameters on conduit flow. This research will use laboratory models to investigate the nature of flow through conduits with relative roughness >5 percent as it pertains to karstic conduit systems, and determine the type of flow regimes are achieved under various relative roughness’s. In addition to roughness, the following parameters will be implemented to the study in an attempt to contribute to the general understanding of morphodynamics contribution to flow in Wakulla Springs: internal geometry, constriction and expansion, bifurcation, and sinuosity.