Turbulent flow measurements

The goal of this course is to introduce students in measurements of the physical quantities in turbulent flows, by use of classical and contemporary measurement techniques. Measurements in turbulent flows are essentially correlated to the physical understanding of Reynolds equations and necessity for turbulence modeling. The main goal of this course is introducing the principles of laser based measurement techniques to students, such as Laser Doppler anemometry and Particle image velocimetry (PIV), as well with fundamentals of other optical anemometer methods.

Upon successful completion of this course, doctoral students should be able to: 1. use the following anemometry methods: laser Doppler anemometry (LDA), particle image velocimetry (PIV), hot-wire anemometry (HWA) probes, as well as other classical methods, 2. measure the pressure field in the fluid, 3. calculate the integral and statistical parameters of turbulence based on the measurement results, 4. perform data acquisition with modern measurement and acquisition systems, as well as their statistical analysis.

Measurement of flow parameters of incompressible and compressible flow with classical measuring techniques. Measurement of the turbulent flow field characteristics. Statistical measurement data processing and analysis. Temporal and space resolutions of flow and measuring system. Vorticity measurements. Time and space correlations. Hot-wire anemometers. Fluid flow visualization. Lasers in anemometry. Flow seeding. Lorenz-Mie theory. Measurement principles of Laser Doppler anemometry (LDA) and plane and stereo Particle image velocimetry (PIV). Construction, tests and adjustments of the Nd:Yag laser. Laser sheet optics. Stereo PIV calibration. Algortihms for data processing and validation. High speed stereo PIV or Time Resolved PIV. Types and architecture of used high speed cameras and lasers. Measurements in turbomachines.

1. Calibration of Conrad probe. 2. Plane and stereo PIV calibration. 3. PIV measurements. 4. Application of algorithms for analysis of experimental data obtained by PIV. 5. Data processing and analysis of LDA measured data. 6. Design, service and calibration of HWA probe.

Doesn't exist. Advice for the second semester: Selected chapters from Fluid Mechanics.

1. Textbooks listed in the references and list of literature provided for students. 2. Čantrak S., Turbulent Flows, lecture handouts on Ph.D. (doctoral) studies, Faculty of Mechanical Engineering University of Belgrade, Belgrade. 3. Benišek М., Fluid Measurements, lecture handouts on Ph.D. (doctoral) studies, Faculty of Mechanical Engineering University of Belgrade, Belgrade. 4. Lecture handouts. 5. Experimental test rigs and equipment in the Laboratory for hydraulic machines and energy systems.

Total assigned hours: 65

New material: 35
Elaboration and examples (recapitulation): 15

Auditory exercises: 0
Laboratory exercises: 0
Calculation tasks: 0
Seminar paper: 0
Project: 0
Consultations: 0
Discussion/workshop: 0
Research study work: 0

Review and grading of calculation tasks: 0
Review and grading of lab reports: 0
Review and grading of seminar papers: 7
Review and grading of the project: 0
Test: 0
Test: 0
Final exam: 8

Activity during lectures: 0
Test/test: 0
Laboratory practice: 20
Calculation tasks: 0
Seminar paper: 40
Project: 0
Final exam: 40
Requirement for taking the exam (required number of points): 30

Ilić D. B., Čantrak Đ. S. (2022): Manual for Fluid Flow Measurements in Laboratory, Faculty of Mechanical Engineering University of Belgrade, Belgrade. (in Serbian); Vukoslavčević P., Petrović D. (2000): Multiple Hot-wire Probes - Measurements of Turbulent Velocity and Vorticity Vector Fields, Montenegrin Academy of Sciences and Arts, Podgorica.; Čantrak Đ.S.(2022):Investigation of the Turbulent Rankine Vortex in Pipe behind Axial Fan Impeller Using Optical (PIV and LDA) Measurement Methods and Visualization,NTI,Vol.59,No.1,MTI,Belgrade(Serb); Tropea C., Yarin A., Fosss J. (Eds.) (2007): Springer Handbook of Experimental Fluid Mechanics, Springer-Verlag, Berlin, Heidelberg.; Raffel M., Willert C. E., Scarano F., Kähler C. J., Wereley S. T., Kompenhans J. (2018): Particle Image Velocimetry, A Practical Guide, 3rd Ed., Springer International Publishing AG