Previous Lectures

Since 2007, DRG has hosted a large number of lectures for an audience of stress and mechanical engineers. With around four lectures a year, many subjects have been presented and not unusual, have been followed-up by a lively discussion during the informal drinks afterwards.


The overview of lectures of previous years can be viewed below. If available, the lecture notes can be downloaded, or – for the more recent lectures – the lecture can be viewed online.


Dynamic Stress Analysis. How to deal with AIV, blast loads, thermal transients, surge, vibrations, pulsations and other transient effects


Speaker: Richard Fawcett of Dynaflow Research Group


In this lecture a range of transient effects will be introduced. It will be shown why they occur and what their effect on a stress analysis is. A number of typical projects conducted by DRG will be used to demostrate how these transient effects can be included in a stress analysis.

2015 Conference Lectures

Solving Vibration Problems in a Two-Phase Flowline


Speaker: Luuk Hennen of Dynaflow Research Group


Multiphase flow in piping systems can pose a serious hazard to system integrity. Slugs that form in piping, due to a two-phase flow that is fed to the system, can impose big shock loads on piping components such as elbows, tees and valves. This can be a one-time event or cyclic by nature. Such phenomenon can therefore result in dynamic behaviour of the piping itself such as vibrations or shifting of the entire line.

Read more


In contrast to pipe vibrations due to connecting rotating equipment, multiphase flow often results in vibrations with a low frequency and high amplitude. Those vibrations can be easily observed by the naked eye. Such vibrations are regularly experienced in furnaces, water feed lines or wellhead lines and can result in mechanical fatigue failure, immediate pipe failure or broken supports. Additionally, the presence of entrapped gas in the system may result in large pressures, significantly exceeding the system design pressures.


Different approaches for solving vibration issues due to two-phase flow will be presented from risk assessment to stress calculations and associated mitigation methods. Often accelerometer measurements are taken to substantiate dynamic calculations. Challenges for such projects include balancing between required system flexibility and sufficiently supporting to absorb slug loads and the assessment of the actual slugging conditions.

The Helyx Hydro Multiphase Solver


Speaker: Oliver Oxtoby of Engys UK


Packed beds and multiphase flows are two common features of industrial processes such as furnaces and reactor vessels, and yet the combination of the two is sparsely covered by the literature on numerical modelling. Further applications include wave action on harbour breakwaters and multi-fluid flows in rock beds.

Read more


In this presentation, we describe our efforts to improve upon the multiphase porous modelling capabilities in the OpenFOAM® toolset. These developments comprise improvements to the handling of free surfaces on non-orthogonal meshes, as well as a numerical method for handling arbitrary heterogeneous porosity fields, possibly including discontinuities, without introducing instabilities or spurious oscillations. This allows for a general porosity distribution to be specified as just another field.


Shockwave interaction on Liquid slugs – Validating a 1D numerical model with large scale experiments


Speaker: Michiel Tukker of Deltares


This presentation discusses the validation of the 1D pipeline simulation software WANDA with experiments. The Wanda simulation software is used to perform multiple studies for gas wells and transport pipelines to assess the functioning of High Integrity Pressure Protection Systems (HIPPS) and the protection against excessive high pressures.

Read more

The experiments have been performed in the large-scale multiphase flow research facility, the Alpha Loop, a 320 m long pipeline system with a diameter of 200 mm.


The project is investigates the behaviour of a slug at rest, which is accelerated due to expanding gas in a long pipeline system. Measurements of the pressures, temperatures and slug position are recorded during the experiment. The movement of the slug has also been recorded using a high-speed camera to get a better understanding of the slug.


The experiment setup has been modelled in WANDA and the model was calibrated using measurements where there is no slug, but only gas flows through the pipeline. The simulation results are then compared with the measured slug velocities, pressures and temperatures from the experiment. The results show good correlation between the calibrated model and the measurements. However, observed 3D phenomena in the experiment due to the large scale are not included in the current 1D model of Wanda, causing the 1D model to predict higher slug velocities than were recorded in the experiment.

Avoiding surge pressure failures due to waterhammer and enclosed vapour pockets


Speaker: Richard Fawcett of Dynaflow Research Group


Sudden transient events in a piping system such as the fast closure of an emergency shut-down valve or the fall out of a pump lead to pressure transients in the flowing fluid. These pressure transients (surge waves) can lead to pressures exceeding the line pressure, or excessive lateral movement and bending stresses in the piping.

Read more


Through a series of cases based on DRG’s project experience typical operating scenarios which can lead to excessive pressure surges will be discussed. Where DRG’s experience ranges from preventing failures at the design phase to root cause analysis of failures in an operating system. Through a number of cases, a series of typical critical issues will be explained and how to design for these so as to ensure a robust system will be demonstrated.


In lines operating at low pressures, cavity pockets may also arise due to surge. As the pressure recovers back above the fluid vapour pressure, the cavity will collapse and the two fluid columns will collide with each other. This collision, like the original surge wave, can result in large amplitude pressure waves. Through a series of examples it will be explained how cavity pockets can form, the detrimental effects these can have on the piping system and how to avoid their occurrence.

Splitting of multiphase flow from a single flowline into a dual riser


Speaker: Ruud Henkes of TU Delft / Shell Projects & Technology


A possible new development concept for Floating LNG may include a single flowline along the sea floor that splits into dual or more flexible risers. Since the gas co-produces condensate and water, design rules are needed for the splitting of the phases at the riser base manifold.

Read more

Ideally the phase volume ratio of the multiphase flow should be fully equal over the two risers and remain the same as in the flow line. The hypothesis is that maldistribution can occur if the gas flow rate in the risers is so low that it gives churn flow or hydrodynamic slug flow in the risers, whereas an equal split is expected if the gas flow rate is sufficiently high to produce annular flow. To study this we have carried out lab experiments and CFD simulations.


The flow facility at the Shell Technology Centre in Amsterdam transports air and water through a 2”, 100 m long flowline, splitting into dual 15 m high risers, having a diameter of 2” or 1.25”. The pressure is atmospheric at the riser top. For the splitting configuration, we tested both a non-symmetric lay-out (so called Branching Tee) and a symmetric lay-out (so-called Impacting Tee). We also created the splitting curve by systematically changing the opening of the chokes at the top of the risers. At low gas flows, for both splitting configurations, a non-symmetric flow split was found, with flip-flopping and hysteresis in the risers. For example, a stagnant liquid flow could develop in one riser, and churn flow in the other riser, with a sudden swap of flow behaviour between the two risers. This maldistribution gradually disappeared as the gas flow rate was increased.


CFD simulations were carried out with the Fluent package using a Volume of Fluid approach for the multiphase flow through the symmetric splitter. As in the experiments, the CFD simulations also give the preference of all flow to be produced though a single riser, with a stagnant liquid column in the other riser. However, in the CFD prediction this misdistribution is found at a lower gas production than in the experiments.


Design and Analysis of Welds subject to Fatigue Loading


Speaker: Frank Bos of Dynaflow Research Group


An overview of analysis and design methods were given for welds subject to fatigue loading. Special focus was given to welds typically found in pressure vessels and piping.

IWEX; A New Ultrasonic Array Technology for Direct Imaging of Defects


Speaker: Niels Pörtzgen of Applus RTD Nederland


IWEX is a novel ultrasonic testing method whose development was initiated by Applus RTD. The result of this emerging technique is an actual image of the inspected volume, rather than a plot of the collected signals, which can be used for accurate characterization in terms of size, position and orientation.


Steel flanges


Speaker: Wies Hageraats of Dynaflow Research Group


  • Design of steel flanges
  • Analysis of steel flanges

Technical challenges for mid-scale LNG Systems


Speaker: Mr. Jan van Houwenhove of Cryonorm Systems


The technical challenges involved in marine LNG fuel systems for inland and seagoing ships, LNG bunkering systems, both land based and installed on ship, LNG regasification systems and LNG/LCNG fill stations.

Ultrasonic Flow Meter


Speaker: Mr. Mo Zarkan of Elster-Instromet


The transit time ultrasonic flow meters (UFM) from the physics of the ultrasound driving the technology to the building components of an UFM to the challenges of designing a UFM.


The presentation is in Dutch.

Soil-structure interaction analysis using PLAXIS


Speaker: Mr. Ronald Bringreve from Plaxis


The presentation will show how PLAXIS can be used for the analysis of soil-structure interaction problems, such as applications involving soil retaining walls, tunnels, offshore foundations and pipelines on the sea bottom.

Read more

Recent developments also enable a coupling between the PLAXIS software and software for structural analysis in which the soil is usually simplified by means of spring constants. This new feature enables a realistic structural analysis, taking into account non-linear soil-structure interaction effects as provided by PLAXIS.


For more information about this presentation, please contact PLAXIS.

2013 Conference Lectures

Flow Assurance Challenges in Oil and Gas Production


Speaker: Prof. Dr. ir. Ruud Henkes of Shell


Flow assurance covers multiphase flow and solids formation in wells, pipelines, and risers, which form part of the oil and gas production system. New developments involve longer transport distances, colder areas, deeper waters, and more complex fluid compositions.

Numerical Study of Low Density Particle Flows in Steelmaking Process


Speaker: Dr. ir. Eelco van Vliet of Tata Steel


A validation study of an in-house developed CFD model for simulating the multiphase flow of low density particles and bubbles encountered in steel making processes.

Flow Assurance Simulators – current status, and what the future might bring


Speaker: Dr. Ove Bratland


The presentation described some of the commercial Flow Assurance simulators, some of the pitfalls to avoid when using them, and also discussed their limitations. Some of the limitations are constantly being reduced by the various R&D projects taking place around the world, while others seem to be more fundamental and therefore harder to counter.

Flow Measurement for Oil and Gas Applications


Speaker: Dr. ir. Peter Lucas of VSL Dutch Metrology Institute


In the presentation the traceability route for natural gas was discussed in more detail. Furthermore, it was discussed why the operating conditions play such an important role for sound and accurate flow metering. Attention was given to flow rate pulsations as well as the impact of deviating process conditions.

Analysis of a closing butterfly valve; efficient workflows and mesh generation in Helyx


Speaker: Eugene de Villier of Engys UK


An actuated butterfly valve simulated using an efficient OPENFOAM®  and HELYX® based process. The main focus of the investigation is to ascertain the turning moment required to overcome the flow induced forces during the opening and closing of the valve. Of secondary interest is the impact of dynamic effects on the system.

Dynamic simulations of a typical gas system with WANDA Gas, incident analysis & remendial design


Speaker: Jos van ‘t Westende of Deltares


When considering the safety of a gas system (e.g. transport pipelines, process vessels), not only the performance under steady conditions should be assessed, but also fast dynamics following unintended valve opening/closure or component failure. A simulation tool that can determine the effects of these fast dynamics and assess the effectiveness of counteracting measures is then a must for designing a safe and reliable system, while not taking too strict and costly measures.

The utility of mimetic methods for computing geophysical flows


Speaker: Prof. Blair Perot of the University of Massachusetts


The earth is a highly heterogeneous and anisotropic medium. This makes the solution of many oil recovery problems more difficult than they might first appear. This presentation was focused on Darcy flow in permeable solids and will show that many of the issues encountered when computing complex flows can be addressed within the construction of the underlying numerical method.

Sloshing simulations using SPH method


Speaker: Ing. Ralf Euser of Femto Engineering


The presentation had two different aspects. First, showing how to analyze the nonlinear sloshing motion of free-surface flows inside closed volumes, with respect to contact pressure and liquid height. In addition to this it was demonstrated how to simulate real fluid-structure interaction (FSI) between liquids and solids.

Surge Analysis of complex piping networks using BOSfluids


Speaker: Ir. Niels Bos of Dynaflow Research Group


Some recent examples of transient flow analysis projects executed using BOSfluids. These cases will illustrate the transient flow phenomena such as bubble collapse, multi-phase flow, slugging and deep vacuum, relevant for transportation systems.


Buried Pipes


Speaker: Wies Hageraats of Dynaflow Research Group


Introduction to buried piping
Basics of soil mechanics
Fundamentals of pipe soil interaction
Buried pipe analysis methods and approaches
Buried pipe stress relief methods



Speaker: Dick de Jong of Lloyd’s Register Nederland


The European guideline Pressure Equipment Directive 97/23/ec

Maasbracht Upgrade Project from a mechanical point of view


Speaker: Piet Beenhakker of Essent


  • Project specifics
  • Project organization
  • Scoping and contracting
  • The process of the project
  • A short explanation of every subcategory of the project


GRP Flanges Design & Assessment


Speaker: Hans Bos of Dynaflow Research Group


  • Theory of flanges
  • Calculation values / calculations / calculation methods

Pipelay Equipment


Speaker: Wouter Slob of Huisman


Mr. Slob explained the boundaries of the Pipelay market and how well the products of Huisman are connected to that. Several Pipelay solutions were presented in detail to provide some technical insight into the world of “Subsea pipelines”.

Travel security for ex-pats and travellers to high risk countries


Speaker: Hein Baartmans of Control Risks


  • Political risk
  • Security risk
  • Integrity risk

Arctic conditions


Speaker: Jan Otten of Shell


Shakalin case study

2011 Conference Lectures

Simulation of Offshore Wave Impacts with a Volume of Fluid Method


Speaker: Tim Bunnik of Marin

Multi-Objective Adjoint Optimization of Flows in Duct and
Pipe Networks


Speaker: Dr. Eugene de Villiers from Engys

Structured Grid Generation for Turbo Machinery Applications using Topology Templates


Speaker: Martin Spel from R. Tech

Lattice Boltzmann Simulations and Application to Multiphase Flows


Speaker: Ir. Sacha Jelic from Exa

CFD Analysis using OpenFOAM of a Finger Type Slug Catcher


Speaker: Frank Bos of Dynaflow Research Group

Deformation and Secondary Atomization of Droplets in Technical Two-Phase Flows


Speaker: Dr. Ing. Ronald Schmehl from Delft University of Technology

Transient Slug Simulations for Gas Piping Systems


Speakers: ” Ir. (Ing.)Frank Odijk from BuNova and Ir. Hans Niessen from Royal Haskoning


Heat Exchangers


Speaker: Johan van der Kamp of Bronswerk Heat Transfer BV


  • Different types of heat exchangers
  • Thermal design
  • Flow modelling
  • Mechanical Design
  • FE Calculations

Two-phase flow in industrial applications


Speaker: Ruud Henkes part-time professor at TU-Delft and Team leader Shell Projects & Technology


  • Two-phase flow as used in the gas and oil industry, particularly during the transport of oil and gas in wells and pipelines.
  • Various operational events, such as normal and turndown operation, start-up and ramp-up, pigging, and the occurrence and mitigation of slugs.
  • Simulation models to design and improve such two-phase flow systems will be presented.



Speaker: Sjaak Nijman of Eriks


  • Theory behind the gasket
  • Production methods
  • Static sealing awareness
  • Emission
  • Basic calculation
  • Types of gaskets with their characteristics
  • Case histories

FPSO related piping and pipe stress aspects


Speakers: Paul Voorhaar and Hugo Kamphuijs of Bluewater


  • Difference between; land based installations, coastal installations and fixed sea based installations
  • Flexibility analysis
  • Loadings


Fiberglass Pipe Systems


Speakers: Henk Luijmes and Kees Rookus of Future Pipe Industries


  • Standards, very different markets
  • Why should we choose for Glassfibre Reinforced materials for piping systems
  • Product ranges and methods of construction
  • Jointing methods
  • Prefabrication
  • Design

Pressure Safety Valves


Speaker: Jean-Paul Boyer of Tyco


  • Sizing
  • Reaction Force
  • Noise
  • Back-pressure



Speakers: Mr. Korenblik and Mr. Lenderink of Siemens


  • Introduction
  • Applications
  • Compressor
  • Centrifugal compressor working principles
  • Compressor selection
  • Mechanical design
  • Aerodynamics
  • Rotordynamics

Reciprocating compressors Acoustical and Mechanical Response


Speaker: Niels Bos of Dynaflow Research Group


  • Elements of Acoustics
  • Aspects of Mechanical Response
  • Examples of Mechanical Response


Het falen van stalen leidingen of vaten


Sprekers: Peter van Houten en Lammert Brantsma van Schielab


  • Introductie over Schielab
  • Ontwerp van een installatie
  • Kwalificatie
  • Lasafwijkingen
  • Oorzaken van falen van stalen leidingen en vaten

Surge Analysis


Speaker: Hans Bos of Dynaflow Research Group.


  • What are surges and what causes them
  • How to reduce the impact of surges
  • Case
  • Conclusions

Mechanical challenges designing a Separator


Spreaker: Frames Separation Technologies


  • Introduction to Separation
  • Oil/Gas/Water Separation basics
  • Challenges and impact Separation on vessel design
  • R&D and Testing trajectories, CFD
  • Conclusion

Use of Bellows en Expansion joints


Spreakers: Mike Luremans of Dynaflow Research Group and Harry Sueters of Hanwel B.V.


  • Why can bellows fail?
  • What are expansion joints
  • Why use expansion joints
  • Forces


Dynamic Module of CAESAR II (is it of any use?)


Speaker: Hans Bos of Dynaflow Research Group


  • Why is the dynamic module of CAESAR II not used more?
  • Function of the dynamical module
  • Dynamic loads are classified based on time history
  • Effect of dynamic loads
  • Required date for dynamical analysis

FEM Software Comparison
(Ansys, FEMAP and ProMechanica)


Speakers: Wies Hageraats of Dynaflow Research Group, Tom Santegoed of Femto Engineering, Mr. Hulst of HEC


During the lecture the comparison of Ansys, FEMAP and ProMechanica was discussed.