2023 Fiscal Year Research-status Report
Elastic turbulence in micro canopy flows, effects of rheology and geometry
| Project/Area Number |
23K19103
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| Research Institution | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
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| Project Period (FY) |
2023-08-31 – 2025-03-31
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| Keywords | Elastic turbulence / Canopy flow / Viscoelasticity / Shear-thinning / Microfluidics / Instability |
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| Outline of Annual Research Achievements |
We have studied the flow of a newtonian fluid and one kind of viscoelastic fluid within and around a micro canopy. Striving towards one of our goals, we have been able to find four different flow regimes as the fluid speed is increased. Those regimes are affected by shear-thinning and by Elastic Turbulence (ET), in the next fiscal year, we plan to study more closely the effect of shear thinning. Finding the transition to ET was another of our goals which we have now achieved, with the conditions for the transition being similar to some previous works and not being strongly affected by geometry.
We have adjusted our plan and started testing different geometrical configurations of the canopy, varying the density of the canopy and the height of the canopy.
We have found some analogies with large scale canopies, always keeping in mind that the basic mechanisms are of course different. Nevertheless, those analogies have allow us to better understand the flow we observe in our system and we hope those analogies will allow to make connections between inertial turbulence and ET in the future. Our results have been presented in two international conferences as a poster and an oral presentation and we are preparing a scientific article to be submitted in the near future.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
We had unforeseen complications with our original microfluidic channel design. An additional instability was triggered by the shape of the outlet which we had to redesign. Additionally, we had to repair one of our devices, delaying the 3D PIV observations of the flow. We had some complications to obtain a viscoelastic liquid with reproducible rheological characteristics, so we had to conduct additional experiments to make sure the fluid would be reproducible.
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| Strategy for Future Research Activity |
We have swapped the order in which we study the different parameters of the system. We started with varying the geometrical characteristics of the channel. In the coming fiscal year we intend to finish researching the effects of canopy height, with one set of experiments with the highest canopy still pending. Following, we will attempt to disentangle the effects of elasticity and shear thinning by using fluids that have only one of those effects, until now we have used a fluid that has shear-thinning and elasticity simultaneously. We will finish with studying the mixing of dyes inside the channel in the elastic turbulent regime.
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| Causes of Carryover |
We found out that we had to perform some testing before purchasing the correct pressure sensors. We intend to buy them as soon as the new budget is approved.
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