Poster

DESY-2014-02139

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The role of bypass elements in leucon-type canal systems: A fluid dynamic study using particle tracking velocimetry in Tethya wilhelma

Jahn, H. (Corresponding author)Extern* ; Herzen, J.Extern* ; Beckmann, F.Extern* ; Nickel, M.Extern* ; Hammel, J.Extern*

2013

Abstract: Sponges are filter feeders relying on an efficient fluid transport system to capture food. In the classical model of flow the aquiferous system consists of incurrent –and excurrent canal system and choanocyte chambers. However, morphological studies in the last years revealed yet another architectural structure in leucon-type canal systems, the so called bypass elements. These structures lead to a direct connection between incurrent and excurrent canal system elements without passing choanocyte chambers. Due to their interconnected nature they are opening up alternative flow pathways.In order to study the fluid mechanics impact of bypass elements in Tethya wilhelma we investigated internal flow fields and canal system architecture. A virtual 3D canal system model was developed based on SRµCT data. This model was utilized in FEM flow simulations. In vivo particle tracking velocimetry measurements of oscular outflow velocity served as initial boundary conditions. Microscopic investigations supplemented detailed morphometric information on the cellular level for various elements of the aquiferous system (e.g. apopylar and prosopylar openings). Results of the simulation were verified in an experimental setup making use of a rapid prototype model. Flow trajectories were visualized by high-speed videography.Our preliminary results indicate a recirculation of water within in the canal system. Within the FEM-models it was not possible to introduce passive flows. The same holds for the developed rapid prototype model. However, principle flow patterns observed in the FEM simulation could be verified. In contrast to a water flow being channeled through bypass elements leading to a reduced flow in the remaining parts of the canal system a recirculation is expected to result in an improved filtering efficiency.

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Contributing Institute(s):

1. DOOR-User (DOOR)
2. Zentrum für Material- und Küstenforschung (HZG)

Research Program(s):

1. DORIS Beamline BW2 (POF2-54G13) (POF2-54G13)
2. DORIS Beamline W2 (POF2-54G13) (POF2-54G13)
3. PETRA Beamline P05 (POF2-54G14) (POF2-54G14)
4. FS-Proposal: I-20120218 (I-20120218) (I-20120218)
5. FS-Proposal: I-20110915 (I-20110915) (I-20110915)
6. FS-Proposal: I-20100327 (I-20100327) (I-20100327)

Experiment(s):

1. DORIS Beamline BW2 (DORIS III)
2. DORIS Beamline W2 (DORIS III)
3. PETRA Beamline P05 (PETRA III)

Appears in the scientific report 2013

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