A Sensor-Based Laminar-Turbulent Wall-Stress Model for Large Eddy Simulation

Wall-modeled large eddy simulations (WMLES) are becoming an increasingly viable tool to study complex unsteady turbulent flows. Conventional wall models applied in these simulations are however not applicable to laminar boundary layers. While these encompass only a tiny fraction of the total surface area, erroneous predictions in this region of...

Analysing Thermal Energy Storage in Residential Buildings: Towards Decarbonization of the Heating Sector

The majority of Dutch homes currently use natural gas boilers to meet their space heating demand. Changes in this significantly large sector are required to achieve the sustainability goals established by the Paris Agreement. Since most renewable energy sources produce electricity, transitioning residential heating systems might cause problems...

A mechanistic modelling framework for swirling gas-liquid vertical pipe flow: Investigating the bubbly to columnar flow transition

This thesis is aimed at developing a fundamental understanding of the key physical mechanisms associated with swirling gas-liquid flow in a vertical pipe, in order to construct a mechanistic model for predicting the flow behaviour. The model is based on quasi-1D reasoning, in analogy to the classical models for gas-liquid flow without swirl. As...

CFD Simulations of the Pazy Wing in Support of the Third Aeroelastic Prediction Workshop

The Pazy Wing test case is a benchmark for the investigation of aeroelastic effects at very large deflections. Tip deformations in the order of 50% span were measured in wind tunnel tests, which renders this model highly attractive for the validation of numerical aeroelastic methods and tools for geometrically nonlinear, large deflection...

Investigating uncertainty in the heating transition: A Sensitivity Analysis case study of the CEGOIA model

The Dutch heating transition involves changing the heating systems of eight million buildings to a sustainable alternative by 2050. Many heating system technologies are available, but deciding which systems are cheapest for all these buildings is a difficult question to answer. Local policymakers are increasingly making use of heating transition...

The potential of renewable energy sources for powering of trolleybus grids: An Arnhem case-study

Trolleybus systems may be a sustainable and cheap alternative to diesel and battery buses. However, to improve sustainablity, the trolleybus system must be powered by renewable energy sources. In this work, a case study on the Arnhem trolleybus grid is performed. First the bus power demands and bus traffic are constructed for the whole system,...

Numerical analysis of the flow past a leading edge inflatable kite wing using a correlation-based transition model

Thorough understanding of flexible wing structural and aerodynamic properties is crucial to reduce uncertainties in the design process of energy generating kite systems. A flexible leading edge inflatable (LEI) tethered kite connected to a drum-generator module is currently being developed by the Airborne Wind Energy research group at TU Delft...

Boundary layer transition modeling on leading edge inflatable kite airfoils

We present a computational fluid dynamic analysis of boundary layer transition on leading edge inflatable kite airfoils used for airborne wind energy generation. Because of the operation in pumping cycles, the airfoil is generally subject to a wide range of Reynolds numbers. The analysis is based on the combination of the shear stress transport...

A sensitivity analysis of CFD transition modelling in the context of vortex roll-up prediction

A sensitivity analysis of the transitional flow over a NACA66₂ - 415 foil and the elliptical Arndt wing is carried out. The SST turbulence model is complemented with the ? - Re ^~_?t transition model to determine the effect of varying turbulence intensity and eddy-viscosity ratio on the integral quantities and...

Modelling sustainability transitions: An assessment of approaches and challenges

Transition modelling is an emerging but growing niche within the broader field of sustainability transitions research. The objective of this paper is to explore the characteristics of this niche in relation to a range of existing modelling approaches and literatures with which it shares commonalities or from which it could draw. We distil a...

Wind turbine rotor aerodynamics: The IEA MEXICO rotor explained

Wind turbines are operating under very complex and uncontrolled environmental conditions, including atmospheric turbulence, atmospheric boundary layer effects, directional and spatial variations in wind shear, etc. Over the past decades, the size of a commercial wind turbine has increased considerably. All the complex and uncontrolled conditions...

Modeling for transition management

A framework for the modeling and simulation of transitions is presented. A transition, “substantial change in the state of a socio-technical system”, typically unfolds over a long timespan. We therefore suggest to use simulation to inform transition managers on the effect of their decisions. Transition models preferably meet five functional...