Fluid mechanics II

lmeca2322  2022-2023  Louvain-la-Neuve

Fluid mechanics II
5.00 credits
30.0 h + 30.0 h
Q1
Teacher(s)
Chatelain Philippe; Deleersnijder Eric; Winckelmans Grégoire;
Language
English
Prerequisites
Mécanique des fluides et transferts 1 [lmeca1321] or equivalent
Main themes
  • Compressible flows in ducts and nozzles
  • Incompressible flows in porous media
  • Potential flows
  • Introduction to transition, turbulence, and CFD
  • Introduction to geophysical and environmental flows
Learning outcomes

At the end of this learning unit, the student is able to :

1 In view of the LO frame of reference of the "Master Mechanical Engineering", this course contributes to the development, acquisition and evaluation of the following learning outcomes:
LO1.1, LO1.2, LO1.3
LO2.1, LO2.2, LO2.3, LO2.4, LO2.5
LO3.1, LO3.2
LO4.1, LO4.2, LO4.3, LO4.4
LO5.4, LO5.5, LO5.6
LO6.1, LO6.2
Specific learning outcomes of the course
At the end of this learning unit, the student will be able to:
  • Use the concepts and the associated equations of the simplified 1-D view, for compressible flows in ducts with friction, and in nozzles without friction, for various boundary conditions (reservoir and outlet); the acquisition and manipulations of the concept and equations being also supported by an experimental laboratory.
  • Apply the theory on flows in a porous media to various cases, linear and non-linear; also decide when non-linearity must be taken into account.
  • Manipulate the simple tools of 2-D potential flow theory to analyze various flows; also the flow past a circle and past an airfoil profile (obtained by transformation of a circle). Draw, using streamlines, flows with and without circulation, and exercise a critical view on the result, based on physics.
  • Comprehend the basic assumption of linear stability theory, the corresponding equations, and their application to the examples presented in class. Solve the equations in simple cases (e.g., for a piecewise linear flow). Comprehend the phenomenological description of the transition to turbulence.
  • Distinguish between the various scales of developed turbulence, also in terms of the energy spectrum (inertial range, dissipation range). Appreciate the impact on resolving scales in turbulent flows.
  • Comprehend the Reynolds averaging approach, also for shear flow, and the simple closure models of the RANS equations.
  • Use critical thinking when using a CFD software to compute a RANS solution of a case with medium geometrical complexity, also as supported by the Best Practice Guidelines (mesh quality, etc.).
  • Comprehend the specific dynamics of turbulent and stratified flows in a rotating reference frame, with specific applications to environmental and geophysical problems, thus enabling the students capable of engaging with researchers, practitioners and relevant officials.
 
Content
Compressible flows in ducts and nozzles
  • Recall of the conservation equations for compressible flows (mass, momentum, energy).
  • Link between isentropic flows at moderate Mach number and ideal incompressible flows.
  • 1-D isentropic flow in a converging-diverging Laval nozzle (subsonic and supersonic cases), sonic conditions and maximum flow rate. Normal shock in a supersonic flow and jump relations. Operating modes of a nozzle.
  • 1-D flow in a duct with wall friction (Fanno)
Incompressible flows in porous media
  • Linear case and model (Darcy).
  • Extended model for nonlinear case with some inertial effects.
  • Examples of applications (e.g., in rock physics, etc.).
Potential flows
  • Singularitties: point vortex, point source/sink, dipole.
  • Obtention of flows using a complex potential.
  • Flow past a circle: case without circulation; case with circulation and associated lift (Magnus effect) .
  • Flow past an airfoil and associated lift.
Introduction to transition, turbulence, and CFD
  • Linear stability theory, and examples of application.
  • Phenomenology of the transition to turbulence.
  • Scales in developed turbulence: energy spectrum and dissipation (Kolmogorov).
  • Reynolds-Averaged Navier-Stokes (RANS) equations; also simplified for shear flows (boundary layer, jet, wake, shear layer).
  • Closure of the RANS equations and simple two-equation models, also near a wall.
  • Best Practice Guidelines, and hands-on sessions using a CFD solver.
Introduction to geophysical and environmental flows
  • Time and space scales of variability.
  • Geohydrodynamic equations.
  • Turbulence, rotation and stratification.
  • Rigid lid and free surface approaches.
  • Relevant case studies (e.g., Ekman boundary layer, 2D turbulence, contaminant transport, linear and nonlinear waves, etc.).
Teaching methods
There are lectures given in an auditorium, each of 2 hours. The student must also acquire some of the course content on his/her own (e.g., content that is a review of material covered in previous mandatory courses, mathematical developments not covered in class).
Sessions of practical exercices (TP) are also organised in class, each of 2 hours and with an assistant, to further develop/detail the concepts covered during the lectures, and to do applications. Some sessions are not organised in class
There are also laboratory sessions led by an assistant (a laboratory on supersonic nozzle flow in groups of 5-6 sudents and with one group report, and a laboratory on introduction to CFD in groups of 2 students and with one report). There are also homeworks.
Evaluation methods
The laboratory sessions and the homeworks correspond to work that is mandatory and that must be performed during the quadrimester; each within a well-defined time period and with a given deadline for the report, that is graded.
It is mandatory to participate physically in each of the laboratory sessions led by an assistant. No laboratory report will be accepted from a student who did not participate in the laboratory session. 
It is not possible to do, or even re-do, any of the work mentioned above outside of the time period that was defined for it within the quadrimester.  
The final exam is a written exam, with questions that can cover all parts of the course (lectures, exercice sessions, laboratories, homeworks).
The calculation of the final grade obtained by the student for the course is a weighted sum of the grade obtained for the final written exam (for 75 %) and of the grades obtained for the work to be performed during the quadrimester (laboratories and homeworks, for 25 %).
If a homework is declared optional, the associated grade will then only serve as a bonus in the calculation of the final grade obtained by the student for the course (meaning that it is used only if this helps increase this final grade).
If the student does not obtain the credit for the class at the deliberation of June, the grade obtained for the work to be performed during the quadrimester remains acquired for the second session of August.
Online resources
Moodle site of the course
Bibliography
Non-exhaustive list:
G.K. Batchelor,  An Introduction to Fluid Dynamics, Cambridge University Press 1967 (reprinted paperback 1994).
F. M. White, Viscous Fluid Flow, second edition, Series in Mechanical Engineering, McGraw-Hill, Inc., 1991.
P. A. Thompson, Compressible Fluid Dynamics, advanced engineering series, Maple Press, 1984.
D.J. Tritton, Physical Fluid Dynamics, Van Nostrand Reinhold, UK, 1985.
P. G. Drazin, Introduction to Hydrodynamic Stability, Cambridge Texts in Applied Mathematics, Cambridge University Press, 2002
P. G. Drazin and W. H. Reid, Hydrodynamic Stability, Cambridge University Press, 1985.
S. B. Pope, Turbulent Flows, Cambridge University Press, 2000
M. Van Dyke, An Album of Fluid Motion, The Parabolic Press, 1982.
H. Burchard, Applied Turbulence Modelling in Marine Waters, Springer, 2002
B. Cushman-Roisin and J.-M. Beckers, Introduction to Geophysical Fluid Dynamics - Physical and Numerical Aspects, Elsevier, 2011 (2nd ed.)
A. Dassargues A., Hydrogeology - Groundater Science and Engineering, CRC Press, 2019
H. B. Fisher et al., Mixing in Inland and Coastal Waters, Academic Press, 1979
P. Kundu et al., Fluid Mechanics, Elsevier, 2015 (6th ed.)
C. Zheng and G.D. Bennett, Applied Contaminant Transport Modeling, Wiley – Interscience, 2002
Teaching materials
  • G. Winckelmans, "Compressible flows", lecture notes (version 2020)
  • G. Winckelmans, "2-D incompressible and irrotational flows", lecture notes (version 2021)
  • G. Winckelmans, "Introduction to hydrodynamic stability", lecture notes (version 2021)
  • G. Winckelmans and Y. Bartosiewicz, "Reynolds-averaged Navier-Stokes (RANS) equations for incompressible flows ", slides (version 2021, as complement to the lecture notes of lmeca1321)
  • E. Deleersnijder, 2021, "Modelling transport processes in geophysical and environmental flows" (slides, problems, appendices, animations)
  • R. Debroeyer and G. Winckelmans, "RANS equations for compressible flows", lecture notes (version 2021)
  • G. Winckelmans, "equations for incompressible flows, and general results for periodic or unbounded flows", lecture notes (version 2021)
  • G. Winckelmans, "Decaying homogeneous isotropic turbulence (DHIT)", lecture notes (version 2021)
Faculty or entity
MECA


Programmes / formations proposant cette unité d'enseignement (UE)

Title of the programme
Sigle
Credits
Prerequisites
Learning outcomes
Master [120] in Mechanical Engineering

Master [120] in Electro-mechanical Engineering