Principles of CFD

Principles of CFD | OpenFOAM Training | Course Modules (4 days)

Velocity, Flow Rate and Conservation

Velocity: plotting profiles, Poiseuille’s Law, no-slip boundary condition (BC), inlet profiles
Flow through a surface: face areas, face zones, calculating areas, flow rates, discharge coefficient
Conservation of mass: derivation, incompressibility, fluxes, intensive and extensive properties
Mathematics: vectors, inner product, Gauss’s theorem, divergence

Forces

Pressure: Bernouilli’s equation, relative and kinematic, gradients, probing pressure data
Stress: Cauchy stress tensor, shear stress, pressure and identity tensor
Newtonian fluid: fluid shear and rotation, rate of deformation tensor, viscosity
Force calculation: force at a surface, force coefficients, particle drag modelling

Momentum

Conservation of momentum: derivation, material derivative, advection, body forces
Tensors: identity tensor, symmetric, skew, transpose, deviatoric, spherical
Coding: mathematical constants, Reynolds number, drag

Internal flows

Wall friction: Darcy-Weisbach friction factor, Reynolds number dependence
Transition: laminar region (friction factor = 64/Re), transition region, turbulence
Turbulent boundary layers: viscous sub-layer, log-law region, 1/7th power law
Wall functions: underlying purpose, standard models, alternative wall models, roughness
Coding: plotting the Moody chart

External flows

Boundary layer thickness: Blasius solution, turbulent separation, turbulent layers
Flow regimes: separation and vortex shedding, transition in wake, shear layers and boundary layers
Turbulence: phenomenon, energy cascade, cost of simulation, turbulent mixing, Reynolds-averaged modelling
Shedding: frequency, Strouhal number, dependence on Reynolds number
Diagnostics: lift coefficient, RMS period of shedding

High-speed flows

Flow regimes: subsonic, supersonic, Mach number, shock and expansion waves
Conservation of total energy: mechanical and internal energy, dissipation, enthalpy
Solution method: flux-splitting, explicit solution, Courant number limit
Coding: skin friction coefficient, energy balance

Heat and thermal physics

Conservation of energy: derivation, total energy, internal energy
Temperature: thermodynamic scale, heat flux, Fourier’s Law, thermal conductivity
Equation of state: ideal gas, the Boussinesq approximation, constant density, compressibility factor
Fluid species: molar mass, Avogradro’s number, gas constant
Heat capacity: at constant volume and pressure, thermal expansion and compressibility
Transport properties: viscosity and thermal conductivity as a function of temperature, Prandtl number
Coding: physical constants

Heat Transfer

Convective heat transfer: Newton’s Law of Cooling, heat transfer coefficient, Nusselt number
Lumped mass temperature: heat balance, Biot number, semi-implicit solution
Conjugate heat transfer: multiple mesh regions, region coupling, coupledTemperature BC
Other: external temperature boundaries, heat sources, thermal boundary layers and wall functions
Coding: thermophysical transport, heat flux, object registry, weighted averages, global sum

Natural convection

Buoyancy: gravitational body force, densimetric Froude number
Boussinesq approximation: linearised temperature equation of state, limitations of linearisation
Pressure: redefinition (p_rgh), boundary fluxes, fixedFluxPressure BC, relative / absolute pressure
Flow: estimating flow speed, turbulence generation, hot plumes, cross-flow

Open channel flow

Solution method: volume of fluid method, MULES, interface compression
Flow regimes: subcritical, supercritical, Froude number, surface wave speed
Mechanical energy: kinetic energy, potential energy, dissipation, hydraulic jump
Coding: inlet and outlet Froude number, measuring interface height

Finite Volume Method

Polyhedral mesh: cells, faces, boundary, patches
Finite volume mesh: cell volumes, cell centre vectors, face area vectors
Matrix equations: matrix construction, sparse matrices
Diffusion: surface normal gradient, Laplacian,
Advection: advective derivative, linear, upwind, linear-upwind, limited-linear interpolation
Time derivative: Euler, backward, Crank-Nicolson schemes, Courant number, time step
Source terms: body force, boundedness
Coding: area calculation

Why attend Principles of CFD?

The knowledge gap in CFD

Computational fluid dynamics (CFD) principally involves fluid dynamics, heat and thermodynamics.
These subjects are traditionally taught to be conveniently examined, with emphasis of pen and paper solutions.
The science (especially thermodynamics) is often described for fluid systems rather than the fluid itself.
Practitioners of CFD therefore have little useful knowledge from their studies to transfer to their work in CFD.
The gap in knowledge — between what a CFD user knows and what they need to know — is widespread and growing.

Teaching fluid dynamics for CFD

This course teaches fluid dynamics, heat and thermodynamics, numerical methods and algorithms for CFD.
We use canonical (study) cases which provide a strong foundation for “real-world” engineering problems.
Solutions are built upon the governing equations of mass, momentum and energy conservation in 3-dimensions.
We demonstrate control volume analysis, which transfers easily to CFD with the finite volume method.
Important empirical and analytical solutions are carefully chosen to demonstrate trends and help validate results.

Preliminary, diagnostic and objective calculations

We encourage the use of quick calculations to prepare and monitor a simulation, and produce key results
Dimensionless numbers are calculated to establish flow and heat transfer regimes prior to simulation.
During the simulation itself, we calculate data which can be monitored and quality checked.
We describe how to extract useful data from the simulation, e.g. to characterise a design.
We teach OpenFOAM’s coded frameworks (code in input files) extensively, for one-time, quick calculations.

Top quality CFD training

The course was created and is delivered by Chris Greenshields and Aidan Wimshurst. It draws on the experience of Chris’s 16 years of OpenFOAM training, involving 800+ days with over 3500 participants. Aidan brings further experience from his Fluid Mechanics 101 channel on YouTube and the ensuing interaction with subscribers. The course builds upon the topics in Notes on Computational Fluid Dynamics: General Principles by Chris and Henry Weller (the creator of OpenFOAM).

CFD Direct

The principles of modern CFD with OpenFOAM, providing critical theoretical and practical knowledge of fluid dynamics, modelling, numerical methods and algorithms.