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Shrestha, S. (author), Dekker, J. (author), Gerritsma, M.I. (author), Hulshoff, S.J. (author), Akkerman, I. (author)In this paper, we build on the work of Hughes and Sangalli (2007) dealing with the explicit computation of the Fine-Scale Greens’ function. The original approach chooses a set of functionals associated with a projector to compute the Fine-Scale Greens’ function. The construction of these functionals, however, does not generalise to arbitrary...journal article 2024
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Hunter, T.P. (author), Hulshoff, S.J. (author)Numerical simulations and optimisation methods, such as mesh adaptation, rely on the accurate and inexpensive use of error estimation methods. Adjoint-based error estimation is the most accurate method, and generally the most costly. A strong contributor to this cost is the need to compute a higher resolution adjoint solution. Here, it is...contribution to periodical 2023
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Hirschberg, L. (author), Bake, F. (author), Hulshoff, S.J. (author)The downstream acoustic response due to the interaction of main-flow oriented vorticity with a choked nozzle in a swirl-free flow was experimentally demonstrated. The response was obtained by means of impulsive radial air injection in the pipe upstream from the nozzle. The resulting downstream acoustic data are shown to obey a scaling rule that...conference paper 2022
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Janssens, M. (author), Hulshoff, S.J. (author)Data-driven parameterizations offer considerable potential for improving the fidelity of General Circulation Models. However, ensuring that these remain consistent with the governing equations while still producing stable simulations remains a challenge. In this paper, we propose a combined Variational-Multiscale (VMS) Artificial Neural...journal article 2022
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Chen, Linfeng (author), Hulshoff, S.J. (author), Dong, Yuhong (author)The underlying physical mechanism of the residual-based large eddy simulation (LES) based on the variational multiscale (VMS) method is clarified. Resolved large-scale energy transportation equation is mathematically derived for turbulent kinetic energy budget analysis. Firstly, statistical results of benchmark turbulent channel flow at Re...journal article 2022
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Hirschberg, L. (author), Bake, F. (author), Knobloch, K. (author), Hulshoff, S.J. (author), Hirschberg, A. (author)An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass...journal article 2022
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Li, X. (author), Hulshoff, S.J. (author), Hickel, S. (author)Proper Orthogonal Decomposition (POD) plays an important role in the analysis of complex nonlinear systems governed by partial differential equations (PDEs), since it can describe the full-order system in a simplified but representative way using a handful of dominant dynamic modes. However, determining a POD from the results of complex...journal article 2022
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Barner, N.M. (author), Ghafourpour, L.D. (author), Güverte, M.S. (author), Modesti, D. (author), Hulshoff, S.J. (author)This work presents a transpacific airliner designed for minimal climate impact, incorporating several novel design features. These include open rotor engines, sustainable aviation fuels, natural laminar flow airfoils, and riblets. The design’s configuration and mission have been optimised simultaneously using a combination of standard...journal article 2022
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Li, X. (author), Hulshoff, S.J. (author), Hickel, S. (author)Adaptive mesh refinement (AMR) is potentially an effective way to automatically generate computational meshes for high-fidelity simulations such as Large Eddy Simulation (LES). Adjoint methods, which are able to localize error contributions, can be used to optimize the mesh for computing a physical quantity of interest (e.g. lift, drag)...journal article 2021
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Hirschberg, L. (author), Bake, Friedrich (author), Knobloch, Karsten (author), Rudolphi, Angelo (author), Kruck, Sebastian (author), Klose, Oliver (author), Hulshoff, S.J. (author)Measurements of sound due to swirl–nozzle interaction are presented. In the experiment a swirl structure was generated by means of unsteady tangential injection into a steady swirl-free flow upstream from a choked convergent–divergent nozzle. Ingestion of swirl by the choked nozzle caused a mass-flow rate change, which resulted in a...journal article 2021
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Li, X. (author), Hulshoff, S.J. (author), Hickel, S. (author)Adaptive Mesh Refinement (AMR) is potentially an effective way to automatically generate computational meshes for high-fidelity simulations such as Large Eddy Simulation (LES). When combined with adjoint methods, which are able to localize error contributions, AMR can generate meshes that are optimal for computing a physical quantity of...journal article 2021
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Hirschberg, L. (author), Bake, F. (author), Knobloch, Karsten (author), Hulshoff, S.J. (author)View Video Presentation: https://doi-org.tudelft.idm.oclc.org/10.2514/6.2021-2286.vid<br/><br/>Quantitative measurements of sound due to swirl-nozzle interaction are presented for the first time. In the experiment a swirl structure was generated by means of tangential injection into a steady swirl-free flow upstream from a choked convergent...conference paper 2021
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Janssens, M. (author), de Vries, I. E. (author), Hulshoff, S.J. (author)Temporary stratospheric aerosol injection (SAI) using sulphate compounds could help to mitigate some of the adverse and irreversible impacts of global warming. Among the risks and uncertainties of SAI, the development of a delivery system presents an appreciable technical challenge. Early studies indicate that specialised aircraft appear the...journal article 2020
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de Vries, I. E. (author), Janssens, M. (author), Hulshoff, S.J. (author)Temporary stratospheric aerosol injection (SAI) using sulphate compounds could help avoid some of the adverse and irreversible impacts of global warming, but comprises many risks and uncertainties. Among these, the direct financial cost and carbon emissions of potential SAI delivery systems have hitherto received only modest attention....journal article 2020
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Hirschberg, L. (author), Hulshoff, S.J. (author), Bake, F. (author)Indirect noise due to the interaction of flow inhomogeneities with a choked nozzle is as an important cause of combustion instability in solid rocket motors and is believed to be important in aircraft engines. A previously published experiment demonstrated that interaction of the nozzle with time-dependent axial swirl can also be a source of...conference paper 2020
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Hirschberg, L. (author), Hulshoff, S.J. (author), Collinet, J. (author), Schram, C. (author), Schuller, T. (author)In solid rocket motors, vortex nozzle interactions can be a source of large-amplitude pressure pulsations. Using a two-dimensional frictionless flow model, a scaling law is deduced, which describes the magnitude of a pressure pulsation as being proportional to the product of the dynamic pressure of the upstream main flow and of vortex...journal article 2018
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Stoter, Stein K.F. (author), Turteltaub, S.R. (author), Hulshoff, S.J. (author), Schillinger, Dominik (author)We initiate the study of the discontinuous Galerkin residual-based variational multiscale (DG-RVMS) method for incorporating subgrid-scale behavior into the finite element solution of hyperbolic problems. We use the one-dimensional viscous Burgers equation as a model problem, as its energy dissipation mechanism is analogous to that of turbulent...journal article 2018
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Stoter, Stein K.F. (author), Turteltaub, S.R. (author), Hulshoff, S.J. (author), Schillinger, Dominik (author)We develop the general form of the variational multiscale method in a discontinuous Galerkin framework. Our method is based on the decomposition of the true solution into discontinuous coarse-scale and discontinuous fine-scale parts. The obtained coarse-scale weak formulation includes two types of fine-scale contributions. The first type...journal article 2018
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Florentie, L. (author), Hulshoff, S.J. (author), van Zuijlen, A.H. (author)An optimization approach is presented that can be used to find the optimal source term distribution in order to represent a high-fidelity vortex-generator (VG) induced flow field on a coarse mesh. The ap- proach employs the continuous adjoint of the problem, from which an exact sensitivity is calculated and used in combination with a trust...journal article 2017
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Florentie, L. (author), van Zuijlen, A.H. (author), Hulshoff, S.J. (author), Bijl, H. (author)Vortex generators (VGs) are a widely used means of flow control, and predictions of their influence are vital for efficient designs. However, accurate CFD simulations of their effect on the flow field by means of a body fitted mesh are computationally expensive. Therefore the BAY and jBAY models, which represent the effect of VGs on the flow...journal article 2017
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