Paper: Fish body geometry reduces the upstream velocity profile in subcritical flowing waters

RIBES ESR Ali Hassan Khan, supervisor Jeffrey Tuhtan, co-supervisor Gert Toming, are all co-authors on a recently published paper titled "Fish body geometry reduces the upstream velocity profile in subcritical flowing waters". The paper is led by Katharina Bensing from Technical University of Darmstadt, Germany. The RIBES authors summarize the paper: 

"A fish’s body shape affects its habitat choices, feeding activities, provides predator avoidance and aids in spawning. We show that a fish’s body can have a large influence on the velocity profile, reducing the flow field at a distance of one body length upstream of the fish. It was also found that the upstream velocity profiles from the nine freshwater fish species investigated can be simplified to single curve, based on the freestream velocity and fish body length under subcritical flow conditions. These findings are significant because they show that conventional point velocity measurements overlook the reducing effect of the fish body on the upstream flow field, creating a systematically biased representation of the velocity experienced by fish in subcritical flowing waters. This bias is illustrated by velocity field maps created with and without the presence of the physical models for three different fish species. Finally, we provide an example of how point velocity measurements can be recalculated to provide upstream velocity field maps closer to “the fish’s perspective”.

Access the full paper here: Bensing, K., Tuhtan, J. A., Toming, G., Khan, A. H., & Lehmann, B. (2022). Fish body geometry reduces the upstream velocity profile in subcritical flowing waters. Aquatic Sciences, 84(3), 32. https://doi.org/10.1007/s00027-022-00863-6