# Joe AlexandersenUniversity of Southern Denmark | SDU · Department of Mechanical and Electrical Engineering

Joe Alexandersen

Ph.D., M.Sc., B.Eng

## About

34

Publications

35,995

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1,070

Citations

Introduction

Joe Alexandersen is an Assistant Professor at the Department of Mechanical and Electrical Engineering, University of Southern Denmark. Joe does research in structural optimisation of mechanical, fluid and heat transfer systems.
See more on: www.joealexandersen.com

Additional affiliations

Education

February 2011 - February 2013

September 2007 - February 2011

## Publications

Publications (34)

This article presents a detailed introduction to density-based topology optimisation of fluid flow problems. The goal is to allow new students and researchers to quickly get started in the research area and to skip many of the initial steps, often consuming unnecessarily long time from the scientific advancement of the field. This is achieved by pr...

This paper presents an experimental study of topology-optimised passive heat sinks produced in a thermally-conductive plastic using material extru-sion additive manufacturing. The thermal performance of the filament is investigated through test printing, thermal conductivity testing and scanning electron microscope imaging. Topology optimisation is...

This paper presents a topography optimisation model for fluid flow with varying channel height. First, the origin of topology optimisation for fluid flow problems is revisited. Here, a Poiseuille-based frictional resistance term was first introduced by Borrvall and Petersson (Int J Numer Methods Fluids 41(1):77–107, 2003) to parametrise regions of...

THIS IS A PREPRINT. FINAL PUBLICATION: https://dx.doi.org/10.1007/s00158-022-03243-8
This paper revisits the origin of topology optimisation for fluid flow problems, namely the Poiseuille-based frictional resistance term used to parametrise regions of solid and fluid. The traditional model only works for true topology optimisation, where it is use...

This paper revisits the optimal thickness profile problem of a single cooling fin using a one-dimensional heat conduction equation with a convection boundary condition. Firstly, in contrast to previous works, we apply an approach using optimality conditions based on requiring stationarity of the Lagrangian functional of the optimisation problem. Th...

Available at https://arxiv.org/abs/2012.04310 : This Brief Note revisits the optimal shape problem of a single cooling fin using a one-dimensional heat conduction equation with convection boundary conditions. Firstly, in contrast to previous works, we apply an approach using optimality conditions based on requiring stationarity of the Lagrangian fu...

A method for density-based topology optimization of heat exchangers with two fluids is proposed. The goal of the optimization process is to maximize the heat transfer from one fluid to the other, under maximum pressure drop constraints for each of the fluids. A single design variable is used to describe the physical fields. The solid interface and...

This paper applies a previously developed framework for topology optimisation of passive cooling to a vertically-oriented electronics cabinet with multiple heat generating chips. The flow field in the cabinet is complex due to the buoyancy generated by the multiple chips interacting with each other. Thus, it becomes difficult to intuitively design...

A method for density-based topology optimization of heat exchangers with two fluids is proposed. The goal of the optimization process is to maximize the heat transfer from one fluid to the other, under maximum pressure drop constraints for each of the fluid flows. A single design variable is used to describe the physical fields. The solid interface...

With the increasing power density of electronics components, the heat dissipation capacity of heat sinks gradually becomes a bottleneck. Many structural optimization methods, including topology optimization, have been widely used for heat sinks. Due to its high design freedom, topology optimization is suggested for the design of heat sinks using a...

This review paper provides an overview of the literature for topology optimisation of fluid-based problems, starting with the seminal works on the subject and ending with a snapshot of the state of the art of this rapidly developing field. "Fluid-based problems" are defined as problems where at least one governing equation for fluid flow is solved...

With the increasing power density of electronics components, the heat dissipation capacity of heat sinks gradually becomes a bottleneck. Many structural optimization methods, including topology optimization, have been widely used for heat sinks. Due to its high design freedom, topology optimization is suggested for the design of heat sinks using a...

This paper treats topology optimization of natural convection problems. A simplified model is suggested to describe the flow of a steady-state incompressible fluid, similar to Darcy’s law for porous media. By neglecting inertia and viscous boundary layers, the flow model is significantly simplified. The fluid flow is coupled to the thermal convecti...

Topology optimization of natural convection problems is computationally expensive, due to the large number of degrees of freedom (DOFs) in the model and its two-way coupled nature. Herein, a method is presented to reduce the computational effort by use of a reduced-order model governed by simplified physics. The proposed method models the fluid flo...

Preprint available at: https://arxiv.org/abs/1904.00182 : This paper treats topology optimization of natural convection problems. A simplified model is suggested to describe the flow of an incompressible fluid in steady state conditions, similar to Darcy's law for fluid flow in porous media. The equations for the fluid flow are coupled to the therm...

Topology optimization of natural convection problems is computationally expensive, due to the large number of degrees of freedom (DOFs) in the model and its two-way coupled nature. Herein, a method is presented to reduce the computational effort by use of a reduced-order model governed by simplified physics. The proposed method models the fluid flo...

This study revisits the application of density-based topology optimization to fluid-structure-interaction problems. The Navier-Cauchy and Navier-Stokes equations are discretized using the finite element method and solved in a unified formulation. The physical modeling is limited to two dimensions, steady state, the influence of the structural defor...

Topology optimization (TO) is an attractive numerical tool to obtain optimized engineering designs, which has been originally developed for mechanical optimization and extended to the area of conjugate heat transfer. With rapid developments in topology optimization models, promising designs have been proposed and presented recently for conjugate he...

This article confirms the superior performance of topology optimized heat sinks compared to lattice designs and suggests simpler manufacturable pin-fin design interpretations. The development is driven by the wide adoption of light-emitting-diode (LED) lamps for industrial and residential lighting. Even for advanced lighting technology as LEDs, a l...

Topology optimised designs for passive cooling of light-emitting diode (LED) lamps are investigated through extensive numerical parameter studies. The designs are optimised for either horizontal or vertical orientations and are compared to a lattice-fin design as well as a simple parameter optimised commercial pin fin design. The different orientat...

The aim of this Thesis is to present efficient methods for optimising high-resolution problems of a multiscale and multiphysics nature. The Thesis consists of two parts: one treating topology optimisation of microstructural details and the other treating topology optimisation of conjugate heat transfer problems.
Part I begins with an introduction...

This paper presents an industrial application of topology optimization for combined conductive and convective heat transfer problems. The solution is based on a synergy of computer aided design and engineering software tools from Dassault Systèmes. The considered physical problem of steady-state heat transfer under convection is simulated using SIM...

This work presents the application of density-based topology optimisation to the design of three-dimensional heat sinks cooled by natural convection. The governing equations are the steady-state incompressible Navier–Stokes equations coupled to the thermal convection–diffusion equation through the Bousinessq approximation. The fully coupled non-lin...

This article presents an application of stress-constrained topology optimization to compliant mechanism design. An output displacement maximization formulation is used, together with the SIMP approach and a projection method to ensure convergence to nearly discrete designs. The maximum stress is approximated using a normalized version of the common...

This work applies topology optimisation to the design of passive coolers for light-emitting diode (LED) lamps. The heat sinks are cooled by the natural convection currents arising from the temperature difference between the LED lamp and the surrounding air. A large scale parallel computational framework is used to perform topology optimisation for...

Conference poster - please see final journal publication: http://link.springer.com/article/10.1007/s00158-015-1279-z

This paper applies topology optimisation to the design of structures with periodic and layered microstructural details without length scale separation, i.e. considering the complete macroscopic structure and its response, while resolving all microstructural details, as compared to the often used homogenisation approach. The approach takes boundary...

The aim of this book chapter is to demonstrate a methodology for tailoring macroscale response by topology optimizing microstructural details. The mi-croscale and macroscale response are completely coupled by treating the full model. The multiscale finite element method (MsFEM) for high-contrast material parameters is proposed to alleviate the high...

This paper demonstrates the application of the density-based topology
optimisation approach for the design of heat sinks and micropumps based on
natural convection effects. The problems are modelled under the assumptions of
steady-state laminar flow using the incompressible Navier-Stokes equations
coupled to the convection-diffusion equation throug...

This thesis deals with topology optimisation for coupled convection problems.
The aim is to extend and apply topology optimisation to steady-state
conjugate heat transfer problems, where the heat conduction equation governs
the heat transfer in a solid and is coupled to thermal transport in a
surrounding fluid, governed by a convection-diffusion eq...

This report deals with the topology optimization of convection problems.
That is, the aim of the project is to develop, implement and examine topology
optimization of purely thermal and coupled thermomechanical problems,
when the design-dependent effects of convection are taken into consideration.
This is done by the use of a self-programmed FORTRA...

## Projects

Projects (5)

A collection of papers covering the fundamentals of fluid flow-driven topology optimisation.

The goal of this ongoing work is to develop efficient computational methods and simplified models for time-dependent fluid and heat transfer problems in order to allow for fast topology optimization.

The goal of this ongoing work is to significantly speed up topology optimisation of conjugate heat transfer problems through the use of simplified models.