Refine
Year of publication
Institute
- Fachbereich Bauingenieurwesen (157) (remove)
Language
- English (157) (remove)
Document Type
- Conference Proceeding (75)
- Article (69)
- Report (6)
- Part of a Book (4)
- Book (1)
- Conference Poster (1)
- Habilitation (1)
Keywords
- metal structure (4)
- steel (4)
- industrial research (3)
- iron and steel industry (3)
- materials technology (3)
- research report (3)
- building industry (2)
- building information modelling (2)
- building materials (2)
- energy efficiency (2)
- research project (2)
- resistance of materials (2)
- 20 fossil-fueled power plants (1)
- 3D printing (1)
- Algal Turf Scrubber (1)
- Algal–bacterial bioflm (1)
- Anammox (1)
- BIM (1)
- Biogas (1)
- Circular bioeconomy (1)
- Energy system (1)
- Freshmen (1)
- HVAC (1)
- Hazard assessment (1)
- Hydraulic structures (1)
- Landslide tsunamis (1)
- Large scale tests (1)
- Mainstream (1)
- Methane (1)
- Mixed integer linear programming (MILP) (1)
- Nitrogen removal (1)
- Open channels (1)
- Overland flow (1)
- PIV (1)
- Partial nitritation (1)
- Physical modeling (1)
- Proper Orthogonal Decomposition (1)
- Q-criterion (1)
- Renewable energy (1)
- Sharing mobility (1)
- Similitude (1)
- Smart Building Engineering (1)
- Solitary waves (1)
- Time-series aggregation (1)
- Typical periods (1)
- VOF (1)
- Wastewater (1)
- anammox (1)
- building safety (1)
- building technique (1)
- business models (1)
- ceramics (1)
- coherent structures (1)
- construction (1)
- dam-break (1)
- designs and models (1)
- drag force (1)
- electro mobility (1)
- emote practical training (1)
- energy disspation (1)
- filtration (1)
- food production (1)
- friction (1)
- gas flow (1)
- guide (1)
- hot gas cleanup (1)
- hydraulic modelling (1)
- ingot (1)
- lockdown conditions (1)
- mainstream deammonification (1)
- mobility behaviour (1)
- model performance (1)
- nitrogen elimination (1)
- numerical model (1)
- physical model (1)
- prefabrication (1)
- remote teamwork (1)
- renewable energy (1)
- roleplay (1)
- small and medium scaled companies (1)
- smart building engineering (1)
- smart engineering (1)
- sustainability (1)
- testing (1)
- thermal insulation (1)
- urban farming (1)
- virtual reality (1)
- wastewater (1)
- wave run-up (1)
As with most high-velocity free-surface flows, stepped spillway flows become self-aerated when the drop height exceeds a critical value. Due to the step-induced macro-roughness, the flow field becomes more turbulent than on a similar smooth-invert chute. For this reason, cascades are oftentimes used as re-aeration structures in wastewater treatment. However, for stepped spillways as flood release structures downstream of deoxygenated reservoirs, gas transfer is also of crucial significance to meet ecological requirements. Prediction of mass transfer velocities becomes challenging, as the flow regime differs from typical previously studied flow conditions. In this paper, detailed air-water flow measurements are conducted on stepped spillway models with different geometry, with the aim to estimate the specific air-water interface. Re-aeration performances are determined by applying the absorption method. In contrast to earlier studies, the aerated water body is considered a continuous mixture up to a level where 75% air concentration is reached. Above this level, a homogenous surface wave field is considered, which is found to significantly affect the total air-water interface available for mass transfer. Geometrical characteristics of these surface waves are obtained from high-speed camera investigations. The results show that both the mean air concentration and the mean flow velocity have influence on the mass transfer. Finally, an empirical relationship for the mass transfer on stepped spillway models is proposed.