Alex Friess: Research Activities and Profile Summaries

Dr. Friess’ research background includes the broad field of experimental fluid dynamics (including laser diagnostics, and aerodynamic design and performance optimization), as well as renewable energy, energy efficiency and engineering education.  He has industrial experience as an entrepreneur in the Solar Energy field, and he has been active as consultant and design engineer working on a variety of projects, including participating in the design and engineering of South Africa’s yacht for the America’s Cup 2007.  Current and past research projects include:

Unmanned Aerial Vehicles (UAV)

  • Lighter than Air (LTA) vehicles (current)

    Computational Fluid Dynamics simulation of flow around an airship

Over the past decade, there has been renewed interest in LTA airship technology. Airships, due to their inherent buoyancy, offer long endurance, with propulsive requirements being reduced to station keeping or flying specific mission profiles.  In addition, LTA vehicles can carry significant payload, and offer Vertical take-off and Landing (VTOL) capability. Small unmanned airships and balloons are regularly used for advertising, and are only now being discovered as sensor deployment platforms. These applications however primarily utilize available vehicles that stem from the traditional advertising role, and as such do not leverage all the advantages of the LTA technology for the remote sensing (RS) application.  

Our work focuses on developing an integrated simulation tool to support the optimization of small LTA vehicles (ranging from fully buoyant to hybrid lift configurations), and thus enable the development of vehicles capable of significantly longer endurance and area coverage than the current generation of multicopter drones, while maintaining VTOL capabilities (and thus be able to operate in constrained spaces such as forests) without the take off and landing limitations of fixed wing drones.

Students with their FAI airship design

Theoretical and computational work is supplemented by LTA prototype design, construction and evaluation.  The ultimate goal is to provide both design and simulation tools for mission optimized small airship drones, and to develop specific hardware for Maine’s remote sensing needs.

This work is in collaboration with the University of Maine School of Forest Resources and the Juneau Icefield Research Program through the University of Maine Climate Change institute, as well as NASA researchers.  The work is supported by the Maine Space Grant Consortium and NASA.



  • Hybrid multi-copter – fixed wing vehicles (current)

The focus here is on the development and testing of a hybrid drone that incorporates VTOL capabilities into a traditional fixed wing UAV, with the intention of extending this range and payload capacity.  The project is conducted by Mechanical Engineering Capstone Students.

Hybrid UAVs at airfield

This project is funded by a NASA EPSCoR grant and conducted in collaboration with researchers and students from the School  of Forest Resources and the remote sensing/geo-spatial lab.

Fluid Mechanics and Aerodynamics

  • Energy efficiency (current)

Dr. Friess is working on building infiltration and infiltration measurement, as well as energy retrofits in extreme climates (i.e. Dubai).

Infiltration visualization through IR imaging

Building infiltration is responsible for up to 34% of energy losses in residential buildings in Maine, and constitutes the single most important energetic efficiency factor (the 2015 Maine Comprehensive Energy Plan Update reports that Maine spends over 3% of its GDP on heating costs, resulting in over 500 Million attributable to infiltration).

Infiltration occurs through cracks and openings in the building walls and ceiling, and can change over time as the building ages and the envelope deteriorates (e.g. see Fig. 1).   Current technology to assess infiltration almost exclusively relies on a Blower Door Test (BDT) upon building commissioning. The BDT creates a steady pressure difference between the inside and the outside of the building, and measures the mass flow rate required by the fan to maintain that pressure difference (typically 50Pa).  Thus real infiltration is not measured, but rather an artificial flow rate due to a constant pressure difference of 50Pa. Furthermore, the one-time blower door test cannot detect progressive deterioration of the building envelope, and as such is unable to diagnose infiltration losses over time. The work conducted here will generate the proof of concept of a distributed differential-pressure recovery time system that remains installed in the building and that is capable of continuously measure infiltration and building envelope health.

The magnitude of the infiltration into a building is related to the fluid characteristics, the size and shape of the opening, and the pressure differential between the inside space and the outside.  While this pressure differential can be directly measured (using sensors inside and outside of the building), the opening characteristics and the infiltration rate are generally unknown.  The system proposed here builds on the transient response between outside pressure fluctuations and inside pressure change2,, to compute the porosity of the envelope and thus to obtain the infiltration rate.  This pressure recovery time is proportional to the infiltration and exfiltration rate of the specific room.

The system, if successful, will measure real, time-integrated infiltration rate (not instantaneous infiltration at an artificial pressure differential as is the case using BDT), and thus, will be capable of providing related information regarding ventilation needs and indoor air quality, and support occupant ventilation decision-making by contrasting behavior with ventilation needs.

This work has been supported through the University of Maine Research Reinvestment Fund.

  • Shellfish aquaculture fluid mechanics (current)

Current rearing of juvenile shellfish is undertaken by using a simplistic device, called an upweller, which passes seawater containing ambient phytoplankton through a layer of juvenile shellfish in order to feed the animals.  Prior work has shown that flow rates, flow distribution and phytoplankton content have a strong impact on the productivity of the shellfish nursery.  To that end, this work aims to develop smart upweller technologies that tailor the ambient flow through the shellfish layer to provide optimal, evenly distributed feeding and excrement flushing to maximize early-stage growth.

Hydrodynamics test apparatus
CFD of upweller cross section

Improved early-stage growth minimizes the number of undersized oysters that must be overwintered in special holding cells, decreases the mortality rate for shellfish laid on the seabed over the winter, reduces the labor associated with rearing slow-growing shellfish, and lastly, accelerates the time to market for the product.  The upweller technology development activities proposed for this project include 1) determining the optimal flow/feeding attributes for American oysters via laboratory experiments, 2) design of smart upweller technologies that achieve the desired fluid flow characteristics to achieve the optimal feeding and waste flushing via further laboratory experiments and computational fluid dynamics simulations, 3) creation of an economic model of the oyster aquaculture process in the Damariscotta River or determining the impact of improved upweller technologies on economic viability and 4) aquaculture industry networking and additional grant writing to support commercialization and adoption of the developed technologies.

This work is conducted in partnership with Dr. Goupee (UMaine Mechanical Engineering), and Dr. Chris Davis (Pemaquid Oyster Co. and Darling Marine Center), and has received funding through the UMaine Research Reinvestment Fund.

  • Sports Engineering and Aerodynamics 
Wind tunnel testing US Speed Skiing Team members at RPI

While spectator sports at venues such as the Olympics, the America’s Cup, and World Championships celebrate the achievement of world class athletes, their peak performance is often made possible by engineers that design and optimize their equipment and training.  This involvement is critical in any sport (one must only think of the advanced swimming suits to reduce drag, or golf balls that fly farther than others), and is particularly noteworthy in sports that utilize sophisticated equipment, such as car and yacht races.  Dr. Friess has experimentally researched the position and equipment of the US Speed Skiing team, and has been active as design engineer and consultant for over 10 years in Europe and Africa, where he participated in the first South African America’s Cup Challenge.

Swimmer dive angle

Sports engineering research continues at UMaine and in particular as part of capstone activities, where for example, a “smart” swimming starting block is under development to assess the optimal impulse for a swimmer diving into the pool.





Recent publications:

    1. Friess, W.A. “Lighter than air vehicles as aerospace focused projects in a mechanical engineering capstone sequence”.  Accepted for publication to 2020 ASEE Annual Conference and Exposition.
    2. Friess, W.A., Goupee, A. “Using continuous peer evaluation in team-based engineering capstone projects: a case study”. IEEE transactions on Education, 2020.  DOI10.1109/TE.2020.2970549
    3.   Friess, W.A., Goupee, A. Transformation of a Mechanical Engineering Capstone Experience, 2019, IEEE Frontiers in Education Conference, Cincinnati, October 16-20 2019.
    4. Rais-Rohani, Friess, Rubenstein “Aerospace Engineering Initiative at the University of Maine”. 2018 ASEE National Conference and Convention, Salt Lake City.
    5. Musavi, Friess, ISherwood and James.  Changing the Face of STEM with Stormwater Research.  International Journal of STEM education, 2018, Online.
    6. Friess, W.A.  “Case study of a discontinued start-up engineering program:  critical challenges faced and lessons learned”.  Higher Education Review, Issue 49(3), September 2017.
    7. Rakshan, K., Friess, W.A.  “Effectiveness and viability of residential building energy retrofits in Dubai”. Journal of Building Engineering. July 2017.
    8. Friess, W.A., Rakshan, K.  “A review of passive envelope measures for improved building energy efficiency in the UAE”.  Renewable and Sustainable Energy Reviews. May 2017.
    9. Friess, Rakshan, and Davis. “A global survey of adverse energetic effects of increased wall insulation in office buildings: degree day and climate zone indicators “.Energy Efficiency, (2016), 1-20. DOI1007/s12053-016-9441-z
    10. Friess, W.A., Martin, E. L., Esparragoza, I.E., Lawanto, O. Improvements in student Spatial Visualization in an introductory engineering graphics course using open-ended design projects supported by 3D printed manipulatives. Proceedings of ASEE National Conference and Convention, New Orleans, June 2016.
    11. Friess and Davis, “Formative homework assessment strategies to improve student time management and learning; WIP”. Proceedings of American Society for Engineering Education Northeast Conference at the University of Rhode Island, April 28-30, 2016


For further information contact Dr. Friess at