Development Of Ultrasonic Imaging Velocimetry In Fluid Mechanics
Universities and Institutes of France
23 Oct 2023
Job InformationOrganisation/Company
Le Havre University
Department
LOMC
Research Field
Physics » Acoustics
Researcher Profile
Recognised Researcher (R2)
Established Researcher (R3)
Leading Researcher (R4)
Country
France
Application Deadline
3 Dec 2023 - 23:59 (Europe/Paris)
Type of Contract
Temporary
Job Status
Full-time
Hours Per Week
35
Offer Starting Date
1 Jan 2024
Is the job funded through the EU Research Framework Programme?
Not funded by an EU programme
Is the Job related to staff position within a Research Infrastructure?
No
Offer DescriptionSince the early 1990s, tracer-based optical methods have emerged as the standard non-invasive flow measurement techniques in research laboratories. While very successful they require optical access and a transparent fluid, thus drastically limiting their applicability. Furthermore, the presence of a dispersed phase, even at low concentrations, can render these techniques useless. To overcome this limitation, non-optical techniques like MRI or X-rays were developed. One of the most promising is ultrasound imaging velocimetry (UIV), derived from medical ultrasound imaging.
UIV derives from the B-mode imaging typically used in medical ultrasound applications. Once an image has been recorded, PIV-like correlation-based algorithms are used to compute the velocity field. With the revolution of ultrafast imaging in the 2010s, the achievable frame rate is now in the kHz range. Furthermore, ultrafast imaging was extended to 3 dimensions (4D-UIV) using a matrix array of transducers. Unfortunately, the increased number of transducers, with the limited electronics available led to a reduced spatial resolution (32×32). To overcome this issue, a new technique, using a row- column addressed (RCA) array with only 128+128 transducers and based on the coherent compounding of orthogonal plane waves, was proposed. This allows for ultrafast, high-resolution 3D ultrasound imaging.
This project aims at optimizing the 4D-UIV technique using a row-column addressed array in a fluid dynamics context in order to achieve time- resolved 3D measurements of fluid flows. Three case studies will be addressed: 3D super-resolution in static suspensions, super-resolution in near-wall measurements, and 3D time-resolved measurements in concentrated suspensions.
The main mission will be to develop ultrasonic imaging velocimetry for fluid mechanics and apply it to three test cases: microscopic characterization of static suspensions, spatially resolved near-wall velocity measurements and 3D time-resolved measurements in concentrated suspensions.
The main activities will be:
Time-resolved ultrasound imaging velocimetry is based on the use of a programmable ultrasound system using a row-column addressed probe. The device will be delivered at the end of 2023. It will be necessary to handle it and develop the programs needed to operate it.
Recent developments, which have led to spectacular achievements, have been carried out in the context of medical imaging. A bibliographical study of this work will be carried out to understand the technique and see how it can be transposed to the field of fluid mechanics. Exchanges with researchers specialized in ultrasound imaging will be possible and encouraged.
Once the ultrasound system has been mastered and the technique understood, it will be necessary to determine the optimal parameters suitable for fluid mechanics experiments.
In the static regime, the aim is to characterize the suspension at a microscopic level. Super-resolved measurements will be used to test the validity of multiple scattering models developed in the laboratory by the team Acoustic of Materials and Structures (AMS).
Using the LOMC Taylor-Couette experiment, we will develop a methodology for time-resolved 3D measurements (UIV-4D) of the velocity field in the near- wall region at high rotational speeds. The trade-off between time resolution and accuracy will be determined. To test this methodology, the data can be compared with optical time-resolved tomographic velocimetry measurements.
The new UIV technique will then be used to measure particle velocity and local concentration for different flow regimes during the transition to turbulence of suspensions in Taylor-Couette flow. These measurements will be carried out for dilute or semi-dilute suspensions, then increasing the concentration as far as the UIV technique allows.
RequirementsResearch Field
Physics » Acoustics
Education Level
PhD or equivalent
Skills/Qualifications
Languages
ENGLISH
Level
Good
Research Field
Physics » Acoustics
Years of Research Experience
1 - 4
Benefits
The candidate will be involved in the development of a new velocimetry technique for fluid mechanics with strong application potential. This will enable him/her to acquire original and unique know-how.
The project involves two laboratory teams: one specialized in acoustics and the other in experimental fluid mechanics. The candidate will therefore benefit from a rich supervisory environment. He/she will also be able to train with contacts in the field of medical ultrasound imaging.
Work Location(s)Number of offers available
1
Company/Institute
LOMC, Université Le Havre Normandie
Country
France
State/Province
Normandie
City
Le Havre
Postal Code
76058
Street
53 rue de Prony
Geofield
Number of offers available
1
Company/Institute
LOMC, Université Le Havre Normandie
Country
France
State/Province
Normandie
City
Le Havre
Postal Code
76058
Street
75 rue Bellot
Geofield
Where to applyCity
Le Havre
Website
https: // www. univ-lehavre.fr/
https: // lomc.univ-lehavre.fr/spip.php?article12=
Street
53, rue de Prony
Postal Code
76600
STATUS: EXPIRED