Previous Research Projects

Characterization of the Bottom Boundary Layer in vegetated flows

The bottom boundary layer (BBL) is the layer of water adjacent to the bottom sediment, this layer is generated due to the friction between the water motion and the sediment bed. The physical structure of this layer has an influence on several critical physicals, chemical and biological processes at or near the bed such as sediment transport, hyporheic exchange and biofilm formation among others.

Due to its importance, the structure of the BBL layer was investigated for bare bed and vegetated flow conditions using the Constant Flow Flume at COEL. High-resolution PIV measurements along with the construction of a physical model of vegetation were used to study the vertical structure of the velocity, stresses and turbulent kinetic energy for different flow conditions and vegetation density within the BBL.

Key contact: Mario Conde-Frias

Email: [email protected]

Detailed measurement of forces in aquatic vegetation

Aquatic vegetation (such as mangroves, seagrass, and salt marshes) plays a crucial role in affecting the local water flows in rivers, estuaries, and coastal regions, and indirectly influences sediment transport as well as biophysical processes. To be able to predict the influence of vegetation, we need to improve our understanding of the forces that act on the vegetation and vice versa. In this experiment we utilized the 25m long Constant Flow Flume to obtain detailed measurements of flow velocities and vegetation forces for a range of conditions, including submerged (e.g. seagrass) and emergent (e.g. salt marsh, mangroves) type vegetation. The results were used to validate and improve a theoretical model that can help coastal managers to predict the effect of aquatic vegetation on local water flows.

Key contact: Arnold Van Rooijen

Email: [email protected]

 

Calibrating Acoustic Doppler Velocimeters (ADV)

ADV are calibrated using the 25m long steady state current flume. Calibration is conducted using the common method of, collecting measurements with the supplied instrument and comparing the results to well calibrated instruments. A comparison is made simultaneously or nearly simultaneously, using a suite of instruments such as other well-calibrated ADV and flow calibration meters.  The availability of high quality research infrastructure and research staff with extensive experience in ADV use, ensures calibrations are conducted to the highest standard.