• Feedforward, Cascade and Model Predictive Control Algorithms for De-Oiling Hydrocyclones: Simulation Study 

      Kulangarakalam Gayathrivallabh, Mishiga Vallabhan; Assumpcao Matias, Jose Otavio; Holden, Christian (Peer reviewed; Journal article, 2021)
      Abstract: Maintaining the efficiency of the produced-water treatment system is important for the oil and gas industry, especially taking into consideration the environmental impact caused of the produced-water. De-oiling ...
    • Finalizing the Wet Gas Laboratory 

      Nedregård, Daniel (Master thesis, 2017)
      This report describes the final stages of development for the small scale wet gas compression test lab. The lab is located at the MTP Institute at NTNU in Trondheim, and it is built in the workshop at campus Valgrinda. The ...
    • Gas Compressor Laboratory Upgrades 

      Rakvåg, Adrian (Master thesis, 2022)
      The compressor laboratory at NTNU Valgrinda created in 2018, need some upgrades to properly function as a anti-surge compressor laboratory. The laboratory is being used by control students to learn how to tune controllers ...
    • Identification and Optimal Control for Surge and Swab Pressure Reduction While Performing Offshore Drilling Operations 

      Tengesdal, Njål Kjærnes; Holden, Christian (Peer reviewed; Journal article, 2020)
      In this paper, an unscented Kalman filter (UKF) coupled with a nonlinear model-predictive controller (NMPC) for a hydraulic wellbore model with multi-variable control and tracking is presented. In a wellbore, high drill ...
    • Implementing a Planning-Based Docking System in Autonomous Vessel 

      Sem, Kristian (Master thesis, 2023)
      Denne oppgaven foreslår en metode for baneplanlegging ved bruk av rasterisering av formfiler fra Environmental Systems Research Institute (ESRI). Disse filene inneholder geospatiale vektordata som blir transformert til en ...
    • L1 Adaptive Anti-Slug Control 

      Ohrem, Sveinung Johan; Holden, Christian; Jahanshahi, Esmaeil; Skogestad, Sigurd (Journal article; Peer reviewed, 2017)
      In many multiphase pipeline-riser systems, anti-slug control is necessary to ensure steady and optimal operation. In this paper, we propose using an ℒ1 adaptive controller as an augmentation to standard PI control to ...
    • Model Predictive Control for a De-oiling Hydrocyclone: A Theoretical and Experimental Study 

      Gaudernack, Amund Egeland (Master thesis, 2021)
      Utslipp av produsert vann er en voksende bekymring på grunn av den negative miljøpåvirkningen. En potensiell løsning er de-oiling hydrosykloner, som er den mest brukte teknologien for å rense produsert vann. Compact Separator ...
    • Model-Based and Model-Free Optimal Control of a Gas Liquid Cylindrical Cyclone 

      Ohrem, Sveinung Johan; Kristoffersen, Torstein Thode; Holden, Christian (Journal article; Peer reviewed, 2018)
      Optimal control is important in the oil and gas industry, where small changes of process variables may have significant economical, environmental and safety impacts. Finding the optimal setpoint for a controlled variable ...
    • Modelica Component Models for Non-diffracting Floating Objects and Quasi-static Catenary Moorings 

      Viswanathan, Savin; Holden, Christian (Chapter, 2020)
      In this paper, the theory behind determining the hydrodynamic response of a floating object in the presence of waves is discussed, followed by a simplification for the case of wave-transparent objects. The Morison equation ...
    • Modelica Component Models for Oceanic Surface Waves and Depth Varying Current 

      Viswanathan, Savin; Holden, Christian (Chapter, 2020)
      In this paper, the theory of progressive ocean-surface gravity-waves is discussed, followed by the concept of the representation of the irregular sea-state by a sea spectrum. Fourier series decomposition of the irregular ...
    • Modeling and Control of Parametric Roll Resonance 

      Holden, Christian (Doctoral Theses at NTNU, 1503-8181; 2011:174, Doctoral thesis, 2011)
      Parametric roll resonance is a dangerous resonance phenomenon affecting several types of ships, such as destroyers, RO-RO paxes, cruise ships, fishing vessels and especially container ships. Worst case, parametric roll is ...
    • Modeling and nonlinear model predictive control of a subsea pump station 

      Ohrem, Sveinung Johan; Holden, Christian (Journal article; Peer reviewed, 2017)
      In this paper we present a model of a pump station consisting of two pumps in parallel with a recycle line, and a nonlinear Model Predictive Control strategy for said pump station with suction pressure as the controlled ...
    • Modelling and Control of Anti-Roll Tanks 

      Hildrestrand, Jon Robert Seth (Master thesis, 2010)
      A ship out at sea is exposed to environmental forces in addition to those generated by the ship's actuators. It is these forces that make the ship move. However, in some cases the ship moves in an undesirable way. Because ...
    • Modelling and Control of Dry and Wet Gas Compressors 

      Tengesdal, Njål (Master thesis, 2017)
      Performing gas compression subsea is an important component for future realisation of complete subsea processing facilities. Gas compressors operating with raw well fluids, categorised as wet gas, enables an increase in ...
    • Modelling and nonlinear control of a wet gas centrifugal compressor 

      Kristoffersen, Torstein Thode; Holden, Christian (Chapter, 2018)
      Production of gas condensate from small and remote gas condensate fields require cost-efficient boosting technology for maintaining an economically satisfactory throughput. Wet gas compressors are a new boosting technology ...
    • Modelling and Simulation of Offshore Drilling Systems 

      Tengesdal, Njål Kjærnes (Doctoral theses at NTNU;2021:324, Doctoral thesis, 2021)
      This thesis presents the results of applying modelling theory, estimation, and control for the efficient formulation of drilling system models for real-time implementation and analysis. Together with modern sensor devices, ...
    • Multiphysical Simulation of Ocean Engineering Systems — Modelica Ocean Engineering Library — Cosimulation for Drilling Riser Analysis 

      Viswanathan, Savin (Doctoral theses at NTNU;2021:162, Doctoral thesis, 2021)
      The advancements in computing has made it possible to carry out integrated simulation of complex multiphysical systems, to better evaluate system performance and safety. The discipline of multiphysical simulation, though ...
    • Nonlinear state and parameter estimation of a gas-liquid cylindrical cyclone 

      Kristoffersen, Torstein Thode; Holden, Christian (Chapter, 2018)
      — New offshore oil and gas discoveries are located at deep waters with long tie-back distances. Development of such fields require compact gas-liquid separation technologies. Efficient operation of such separators require ...
    • An Open-Source Python-Based Boundary-Element Method Code for the Three-Dimensional, Zero-Froude, Infinite-Depth, Water-Wave Diffraction-Radiation Problem 

      Viswanathan, Savin; Holden, Christian; Egeland, Olav; Greco, Marilena (Journal article; Peer reviewed, 2021)
      In this paper, a new open-source implementation of the lower-order, 3-D Boundary Element Method (BEM) of solution to the deep-water, zero Froude-number wave-body interaction problem is described. A validation case for ...
    • Optimal Dynamic Force Mapping for Obstacle-Aided Locomotion in 2D Snake Robots 

      Holden, Christian; Stavdahl, Øyvind; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2014)
      Snake robots are biomimetic robots highly suited for traversing challenging terrain where traditional robots have difficulty moving. A key aspect is obstacle-aided locomotion, where the snake pushes against the environment ...