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Turbulence

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Course Unit Code338-0527/02
Number of ECTS Credits Allocated3 ECTS credits
Type of Course Unit *Optional
Level of Course Unit *Second Cycle
Year of Study *Second Year
Semester when the Course Unit is deliveredSummer Semester
Mode of DeliveryFace-to-face
Language of InstructionCzech, English
Prerequisites and Co-Requisites Course succeeds to compulsory courses of previous semester
Name of Lecturer(s)Personal IDName
KOZ30prof. RNDr. Milada Kozubková, CSc.
BOJ01doc. Ing. Marian Bojko, Ph.D.
BLE02doc. Ing. Tomáš Blejchař, Ph.D.
Summary
The subject is focused on modeling possibilities of turbulent / laminar fluid flow in different areas of mechanical engineering, civil engineering, aviation, metallurgy and other fields, where there are devices and machines that contain fluid, or use it for their activities. The finite volume method (MKO) will be used to solve the system of flow equations. They will be created during the lessons 2D and 3D CFD models of real equipment in ANSYS Fluent. In the course of education, the program DesignModeler will be used to create geometry and the program ANSYS Meshing will be used to create a computational grid.
Learning Outcomes of the Course Unit
Students will become familiar with the possibilities of simulation of turbulent / laminar flow of fluids in various fields of engineering, civil engineering, aviation, metallurgy and other areas where there are equipment and machinery, which contain liquid. They create 2D and 3D CFD models of real devices in an ANSYS-Fluent. When creating a geometric model, students will build on previous knowledge of drawing in higher CAD systems. Students will analyse the assignment of tasks solved in the basic knowledge acquired in the course Fluid Mechanics. They will draw the CFD simulation of airflow around the body, heat transfer, the interaction of two different fluids. Students will interpret the results of simulations and analyse the flow.
Course Contents
1. Introduction, numerical modeling of fluid flow - various commercial systems, ANSYS, types of tasks in the program ANSYS
2. Coordinate system, the Navier-Stokes equations (laminar flow), counting rules, examples, flow in tube, creation of geometry in the ANSYS Workbench, principle of creation computational area and modification of geometry, creation of computational grid, process in creation grid. Demonstration of grid.
Practice treatment geometry and creating a grid on real geometry.
3. The physical meaning of turbulence, methods of of modification geometry and creation of grid on real geometry created in CAD. Mathematical models of turbulence, the N-S equation, continuity equation, Reynolds stress, time averaging, Reynolds rules, Boussinesq 's hypothesis, two equation turbulence model.
CFD model of flow in a sudden extension of cross-flow, laminar flow regime. import of grid, compatible grids.
4. Transfer of mass, momentum and heat, conduction and convection in heat transfer, determination of thermal power, thermal gradient, heat transfer coefficient, Nusselt number.
5. Integration of the finite volume method for one-dimensional continuity equation and momentum equations, an iterative cycle, the interpolation scheme, convergence (residuals), the definition of species-multiphase model, the cavitation model, combustion model, model of thermal radiation, definition of chemical reaction.
Determination of pressure loss in the sudden expansion, the model testing the effect of turbulence on value of loss factor. Defining the boundary conditions function, measured data. Export data from the postprocessor, data analysis in EXCEL.
6. Boundary conditions, conditions of input and exit, conditions of symmetry, periodic conditions, conditions on the wall, the wall heat transfer, time-dependent task. Methods of solving discretized equations, LGS solver, multigrid.
7. Overview of turbulence models available in CFX, the zero-equational model, k- model, RNG k- model, the RSM model, the LES models, SAS, DES. Optimal choice of model, field of use of turbulence models.
8. Flow of real fluids, the law of conservation of mass, momentum and energy for compressible flow, supersonic flow, shock waves. Co- and counterflow heat exchangers of types water-water or water-air. Specify individual seminar works and discussion.
Solution of individual seminar work.
9. The flow of solid particles and drops, the species and their definitions. Definition of tension and buoyancy drops coefficient - solid particles. .: Special settings in CFX, multidomain simulation, paralel calculations. Integration of CFX in Workbench, the general procedure for the design and calculation of machine.
Solution of individual seminar work.
Recommended or Required Reading
Required Reading:
INCROPERA, F., P. ET AL. Fundamentals of heat and mass transfer. 6th ed.. Hoboken : Wiley, c2007 – xxv. 997 s. ISBN 0-471-45728-0.

SHAUGHNESSY, E. J., KATZ, I. M., SCHAFFER, J. P. INTRODUCTION TO FLUID MECHANICS. New York: Oxford University Press, Inc. 2005. p. 1018.

ANSYS Fluent Theory Guide (Release 18.2). 2017.
BLEJCHAŘ, T. Turbulence Modelování proudění – CFX. Ostrava: VŠB-TU Ostrava, 2012. 263 s. ISBN 978-80-248-2606-6. Dostupnost < http://www.338.vsb.cz/studium/skripta/>.

KOZUBKOVÁ, M., BOJKO, M., BLEJCHAŘ, T. Modelování přenosu tepla, hmoty a hybnosti. Ostrava: VŠB-TU, 2019, 224 s. Dostupnost < http://www.338.vsb.cz/studium/skripta/>.

KOZUBKOVÁ, M., BOJKO, M. Modelování přenosu tepla, hmoty a hybnosti- návody do cvičení. Ostrava: VŠB-TU, 2019, 116 s. Dostupnost < http://www.338.vsb.cz/studium/skripta/>.

BOJKO, M. Návody do cvičení „Modelování proudění“ – Fluent. Ostrava. VŠB-TU Ostrava, 2008, 141 s. ISBN 978-80-248-1909-9. Dostupnost < http://www.338.vsb.cz/studium/skripta/>.
Recommended Reading:
RODI, W., FUEYO, N. Engineering Turbulence Modelling and Experiments 5. First edition. Oxford: ELSEVIER SCIENCE Ltd. 2002. p. 1010. ISBN 0-08-044114-9.

ANSYS Fluent Tutorial Guide (Release 18.2). 2017.

ANSYS Fluent User’s Guide (Release 18.2). 2017.
KOZUBKOVÁ, M. Modelování proudění tekutin FLUENT, CFX. Ostrava: VŠB-TU, 2008, 115 s. ISBN 978-80-248-1913-6. Dostupnost < http://www.338.vsb.cz/studium/skripta/>.

BOJKO, M. 3D PROUDĚNÍ – ANSYS FLUENT - učební text. Ostrava. VŠB-TU Ostrava, 2012, 314 s. ISBN 978-80-248-2607-3. Dostupnost < http://www.338.vsb.cz/studium/skripta/ >.

ANSYS Fluent Tutorial Guide (Release 18.2). 2017.
Planned learning activities and teaching methods
Lectures, Tutorials
Assesment methods and criteria
Task TitleTask TypeMaximum Number of Points
(Act. for Subtasks)
Minimum Number of Points for Task Passing
Exercises evaluation and ExaminationCredit and Examination100 (100)51
        Exercises evaluationCredit35 25
        ExaminationExamination65 20