Publications

You can also find my articles on my Google Scholar profile.

Journal Papers

Tripping effects on model-scale studies of flow over the DARPA SUBOFF

Journal of Fluid Mechanics, 2023

Nicholas Morse, Krishnan Mahesh

Trip-resolved large-eddy simulations of the DARPA SUBOFF are performed to investigate the development of turbulent boundary layers (TBLs) in model-scale studies. The primary consideration of the study is the extent to which the details of tripping affect statistics in large-eddy simulations of complex geometries, which are presently limited to moderate… Read more

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Effect of tabs on the shear layer dynamics of a jet in cross-flow

Journal of Fluid Mechanics, 2023

Nicholas Morse, Krishnan Mahesh

Direct numerical simulations (DNS) of a jet in cross-flow (JICF) with a triangular tab at two positions are performed at jet-to-cross-flow velocity ratios of $R = 2$ and $4$ with a jet Reynolds number of 2000 based on the jet’s bulk velocity and exit diameter. The DNS and dynamic mode… Read more

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Large-eddy simulation and streamline coordinate analysis of flow over an axisymmetric hull

Journal of Fluid Mechanics, 2021

Nicholas Morse, Krishnan Mahesh

A new perspective on the analysis of turbulent boundary layers on streamlined bodies is provided by deriving the axisymmetric Reynolds-averaged Navier–Stokes equations in an orthogonal coordinate system aligned with streamlines, streamline-normal lines and the plane of symmetry. Wall-resolved large-eddy simulation using an unstructured overset method is performed to study flow… Read more

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Thesis

High-fidelity unstructured overset simulation of complex turbulent flows

University of Minnesota, 2023

Nicholas Morse

The goal of this dissertation is to provide insight into the underlying physics of two sets of complex flows: (i) the axisymmetric and appended DARPA SUBOFF and (ii) tabbed jets in crossflow. The accurate simulation of the flow around marine vessels such as the DARPA SUBOFF is critical for maneuvering… Read more

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Conference Papers

Optimized timing schemes for multi-pulse shake-the-box particle tracking velocimetry

AIAA SciTech Forum, 2023

Michael Fenelon, Yang Zhang, Louis Cattafesta III, Nick Morse, Krishnan Mahesh, Lanyu Li, Zhao Pan

Particle Tracking Velocimetry (PTV) is a non-intrusive measurement technique that is gaining increasing popularity in the experimental fluid mechanics community. The basic working principle is to determine three-dimensional Lagrangian particle tracks via multiple exposures separated by known time intervals as seen by at least three cameras. The practical extension of… Read more

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Large-eddy simulation of submerged marine vehicles

34th Symposium on Naval Hydrodynamics, 2022

Nicholas Morse, Thomas Kroll, Krishnan Mahesh

Large-eddy simulation (LES) using an unstructured overset grid method (Horne and Mahesh, 2019) is used to explore several building-block problems of interest for submerged marine vehicles, including the bare and appended DARPA SUBOFF and the open and ducted propeller David Taylor Model Basin (DTMB) 4381 in crashback. An emphasis is… Read more

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Large-eddy simulation of marine flows over complex geometries using a massively parallel unstructured overset method

33rd Symposium on Naval Hydrodynamics, 2020

Thomas Kroll, Nicholas Morse, Wyatt Horne, Krishnan Mahesh

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Conference Abstracts

A simulation framework for nanodroplet breakup in top-down nanoparticle production

AIChE Annual Meeting, 2024

Nicholas Morse, Johan Remmelgas, Johannes Khinast

Nanoparticles have shown great promise as a pharmaceutical carrier, evidenced most strongly by the success of lipid nanoparticles as carriers for mRNA vaccines during the COVID-19 pandemic. However, the fundamental processes that govern nanoparticle formation are still not well understood and particle size predictions are generally reliant on empiricism. Numerical… Read more

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The shear layer structure of a tabbed jet in crossflow

75th Annual Meeting of the APS Division of Fluid Dynamics, 2022

Nicholas Morse, Krishnan Mahesh

Passive devices such as tabs have been shown to be an effective method of altering the characteristics of regular and transverse jets, although the specifics of how tabs affect jet flow fields are not well understood, especially for jets in crossflow. Direct numerical simulations of a tabbed jet in crossflow… Read more

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Optimizing dt for MP-STB in particle tracking velocimetry

75th Annual Meeting of the APS Division of Fluid Dynamics, 2022

Michael Fenelon, Louis Cattafesta III, Yang Zhang, Krishnan Mahesh, Nick Morse

Multi-pulse tracking velocimetry is gaining increasing popularity in the fluid mechanics community. The basic working principle is to trace the particle displacements in multiple images separated by specified time intervals, and then the Lagrangian particle path and associated quantities can be determined. A recent breakthrough in particle tracking velocimetry was… Read more

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Streamline coordinate analysis of the flow past an axisymmetric body computed by large-eddy simulation

74th Annual Meeting of the APS Division of Fluid Dynamics, 2021

Nicholas Morse, Krishnan Mahesh

Turbulent boundary layers with streamline curvature are ubiquitous in engineering applications, and the flow around axisymmetric bodies is further complicated by transverse curvature. We analyze results of wall-resolved large-eddy simulation of an axisymmetric hull in an orthogonal coordinate system defined by streamlines and streamline-normal lines. The numerical algorithm used in… Read more

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Large-eddy simulation of submerged vehicles using an unstructured overset grid method

73rd Annual Meeting of the APS Division of Fluid Dynamics, 2020

Nicholas Morse, Krishnan Mahesh

Appended axisymmetric bodies are of particular interest in marine vehicle applications, in which the wakes and horseshoe vortices of the appendages are ingested by the propulsor. We discuss the application of a novel unstructured overset method to wall-resolved large-eddy simulation (LES) of an appended hull geometry. The numerical algorithm used… Read more

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Towards large-eddy simulation of maneuvering vehicles using an unstructured overset grid method

72nd Annual Meeting of the APS Division of Fluid Dynamics, 2019

Nicholas Morse, Wyatt Horne, Krishnan Mahesh

We discuss the development of large-eddy simulation (LES) capability towards the simulation of maneuvering vehicles using the novel unstructured overset numerical algorithm developed by Horne and Mahesh [J. Comput. Phys (2019) 376:585-596]. This method addresses the discrete conservation and scaling challenges of overset methodologies and allows for simulation of flows… Read more

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Investigation of particle lift off in a turbulent boundary layer

70th Annual Meeting of the APS Division of Fluid Dynamics, 2017

Diogo Barros, Yi Hui Tee, Nicholas Morse, Ben Hiltbrand, Ellen Longmire

Entrainment and suspension of particles within turbulent flows occur widely in environmental and industrial processes. Three-dimensional particle tracking experiments are thus conducted in a water channel to understand the interaction of finite-size particles with a turbulent boundary layer. A neutrally buoyant sphere made of wax and iron oxide is first… Read more

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