Aerospace Engineering

Aircrafts of the future: Boosting aerodynamic performance by engineered surface vibrations

Jeff Zehnder — Mon, 24 Mar 2025 16:34:49 +0000

Aircrafts of the future: Boosting aerodynamic performance by engineered surface vibrations Jeff Zehnder Mon, 03/24/2025 - 10:34

Jeff Zehnder

“This is probably the most radical conceptual advancement for airplanes since the replacement of propellers with jets.” – M.I. Hussein

Mahmoud Hussein is not pulling punches about the potential impact of a major aerospace materials research project.

As the principal investigator of a $7.5 million, five-year Department of Defense Office of Naval Research (ONR) Multidisciplinary University Research Initiative (MURI), Hussein is leading an effort to reshape the fundamental character of fluid-structure interactions to reduce drag on high-speed aerospace vehicles—the focus of the project.

“Since the dawn of aviation, aircraft design has been based on the premise of shaping the surface of the vehicle to create lift and minimize drag. Our team is pursuing a new paradigm where the phononic properties, or intrinsic vibrations, of a surface or subsurface provide an additional pathway to interact with the airflow, to enhance the vehicle performance in an unprecedented manner,” said Hussein, the Alvah and Harriet Hovlid Professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at the ��ƷSM��ӰƬ.

Hussein also has a courtesy appointment in the Department of Physics and an affiliation with the Materials Science and Engineering Program.

MURI Partners

��ƷSM��ӰƬ

Mahmoud I. Hussein
Professor & Principal Investigator
Armin Kianfar
Post-Doctoral Associate
Adam Harris
PhD Student

University of Maryland

Christoph Brehm
Associate Professor

Johns Hopkins University

Kevin Hemker
Professor

Purdue University

Joseph Jewell
Associate Professor

Applied Physics Laboratory

Keith Caruso
Principal Staff Engineer
Ken Kane
Researcher

University of Kentucky

Alexandre Martin
Professor

Case Western Reserve University

Bryan Schmidt
Assistant Professor

Office of Naval Research (Program Directors)

Eric Marineau
Eric Wuchina

Phononic Subsurfaces

Turbulent airflow is detrimental to the fuel economy and the surface temperature of aircrafts as they soar through the atmosphere. This research aims to mitigate the transition to turbulence using phononic subsurfaces (PSubs) – synthetic designed materials affixed beneath the surface of a wing or vehicle body that passively manipulate small-amplitude vibrations, and by extension flow fluctuations, point-by-point along the surface.

Turbulence and Fuel Economy

Passenger planes consume over 10,000 gallons of jet fuel on a single cross-country trip, so improvements in fuel economy could lead to big savings for airlines. The potential in hypersonic crafts is even more dramatic.

Hypersonic vehicles travel at velocities at least five times the speed of sound. The turbulence that results from such speeds causes the surface of the vehicles to heat up to thousands of degrees, requiring they be constructed of exotic, expensive materials.

“By introducing a phononic subsurface to precisely shape the vibrations along the surface, we can alter the way the air interacts with the vehicle such that we ultimately don’t need to come up with exceedingly high-temperature-resistant materials,” Hussein said. “We’re passively manipulating instabilities in air flow in a manner that is favorable in the boundary layer where the vehicle meets the surrounding air.”

2015 to Today

The concept of PSubs was discovered by Hussein. The work began from a collaboration over 15 years ago between Hussein and then ��ƷSM��ӰƬ Professor Sedat Biringen, who died in 2020. As leaders in the newly-born research area of phononics and the longstanding field of fluid dynamics, respectively, they worked together to theoretically demonstrate–for the first time–a way to manipulate phonons to improve the efficiency of flight, with tremendous potential for the aerospace industry and prospects for application to water vessels as well.

Recently Hussein gathered a team of experts from across the country to take the concept of PSubs to the next level with this hypersonics MURI grant. Over the duration of the project, the group will develop high-fidelity models and fabricate functional prototypes to effectively characterize and demonstrate the technology in high-speed wind tunnels.

“We’re most confident about this endeavor, because the idea is rooted in fundamental science marrying–in quite a sophisticated fashion–fluid dynamics with condensed matter physics as well as with the emerging field of elastic metamaterials,” Hussein said.

“This is probably the most radical conceptual advancement for airplanes since the replacement of propellers with jets.” – Mahmoud Hussein is not pulling punches about the potential impact of a major aerospace materials research project.

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Advancing real-time data compression for supercomputer research

Jeff Zehnder — Thu, 13 Mar 2025 18:29:48 +0000

Advancing real-time data compression for supercomputer research Jeff Zehnder Thu, 03/13/2025 - 12:29

Jeff Zehnder

Alireza Doostan is leading a major effort for real-time data compression for supercomputer research.

A professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at the ��ƷSM��ӰƬ, Doostan is the principal investigator on a $1.2 million Department of Energy project to change how researchers handle the massive amounts of data that result from complex physics problems like modeling turbulence and aerodynamics for air and space craft.

Compressing data is nothing new when it comes to computing, but advances in high- performance systems are now creating so much data that it becomes impossible to store for later analysis.

“Computing power has increased drastically, but moving and storing that data is becoming a bottleneck. We have to reduce the size of the data generated through large scale simulation codes,” Doostan said.

While some scientific analysis of turbulence flows can be completed faster on ever larger high-performance computing platforms, much of the information must be discarded because the scope of the data is too vast to store, making it impossible to conduct later assessments.

“There is a lot of structure and physics embedded in the data that ideally needs to be preserved to study complex flow physics or develop faster models,” Doostan said.

The goal of the grant is to both maintain accuracy of modeling data while decreasing its complexity, and critically, allowing it to be stored by compressing it in-situ, or in real-time as it is created during modeling. This is not currently possible for large-scale models, as existing technology often requires some or the entire modeling simulation be completed before compression can begin.

Joining Doostan on the project is a team of ��ƷSM��ӰƬ faculty, including Ken Jansen and John Evans, both also from Smead Aerospace, and Stephen Becker from applied math.

The team is focused on development of both traditional and deep neural models for massively parallel implementation of novel linear and non-linear dimensionality reduction techniques. It is a major undertaking, bringing together researchers with a broad range of backgrounds, including computational physics and sciences, discretization, machine learning, linear algebra, and statistics.

“This is a very interdisciplinary problem,” Doostan said. “This is not a problem one person can solve. You need a team.”

For Jansen, whose research focuses on turbulence modeling, an advance in compression could lead to significant progress across the spectrum of high-performance computing.

“This data compression research is critically important to provide access to the dynamics of our simulations,” Jansen said. “As simulations have passed petascale and are now exascale, it has become impractical to write the full solution fields to disk at a sufficient frequency and count, owing to the broad range of spatial and temporal scales of turbulence.”

The group has completed soon-to-be-published research showing strong promise for their approach. They are now working to scale up their algorithms to work at scale on supercomputing platforms like ��ƷSM��ӰƬ’s Blanca cluster as well as Department of Energy systems.

“There is still a lot to be done, but our early work has shown success and only increases the computational load by less than five percent,” Doostan said.

The three-year award runs through fall 2027. Doostan is hopeful their final product will include publicly available next-generation compression software for general use by all simulation practitioners.

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��ƷSM��ӰƬ among top colleges for Indigenous students

Charles Ferrer — Wed, 13 Nov 2024 20:34:04 +0000

��ƷSM��ӰƬ among top colleges for Indigenous students Charles Ferrer Wed, 11/13/2024 - 13:34

Charles Ferrer

The American Indian Science and Engineering Society (AISES) has recognized ��ƷSM��ӰƬ as one of the top 200 colleges for Indigenous students in its 2024-2025 national rankings.

��ƷSM��ӰƬ's AISES chapter attends the 2024 national AISES Conference in San Antonio.

AISES, a national organization dedicated to increasing Indigenous representation in STEM fields, evaluated schools based on the strength of their support programs for Native students, as well as undergraduate enrollment and graduation rates.

The AISES chapter at ��ƷSM��ӰƬ serves as a community for Indigenous students in the College of Engineering and Applied Science and across campus, connecting those interested in STEM and supporting them academically and professionally. This recognition reflects ��ƷSM��ӰƬ’s commitment to fostering an environment where Indigenous students can thrive in STEM—a commitment embodied by the leaders of its AISES chapter.

Noelle Bagola, the chapter’s treasurer, said her journey with AISES has empowered her professionally and personally.

“Being part of AISES allowed me to grow as a leader,” she said.

Through her involvement, Bagola developed skills in areas she once found challenging, like connecting with professionals at conferences and building strong peer relationships.

“Now, I feel confident communicating with people and stepping up to help others. Becoming a leader has been my biggest accomplishment with AISES.”

For Shellene Redhorse, AISES chapter president and a third-year aerospace engineering student, the chapter’s impact extends beyond ��ƷSM��ӰƬ’s campus.

“A lot of what AISES does is about supporting our members and the Indigenous community,” she said. “The Indigenous community at ��ƷSM��ӰƬ may be small, and the STEM students within that community are even more rare, but we are here.”

One of her proudest achievements was taking students to this year’s national AISES conference in San Antonio, where they connected with other Native scientists. Redhorse also highlighted the chapter’s outreach to Indigenous students in Denver, where they host hands-on STEM activities, including rocketry demonstrations at Lake Middle School.

“We’re hoping to inspire middle-schoolers by showing them what a future in STEM could look like,” she said.

“When I was in school, I didn’t think a STEM career was possible for me until I got to work on hands-on projects. I know many Native students don’t have those opportunities, so we’re working to change that.”

Looking forward, AISES aims to establish a more permanent support network for Native students in Denver, opening more pathways into STEM fields.

Indigenous Knowledge and STEM

AISES participated in the 2023 First Nations Launch as the ‘CU Trailblazers’, sweeping first place in all their categories and a grand prize trip to the Kennedy Space Center.

Both Bagola and Redhorse draw from Indigenous knowledge to inform their approach to STEM.

Redhorse, who is of Navajo (Diné) and Chickasaw descent, described how her cultural heritage shapes her engineering perspective.

“In our culture, we observe nature closely—how animals act, how weather patterns shift, even how the stars guide us. Our ancestors used this knowledge for everything from growing crops to building structures,” she said.

Inspired by these traditions, she incorporates Indigenous wisdom into school projects.

“I remember building a small rover in sixth grade based on how a beetle moved away from light. It’s that respect for nature and deep observation that really inspires me.”

Redhorse often reflects on Navajo understandings of stars and space, which she sees as especially relevant to her studies in aerospace. She also appreciates Indigenous approaches to sustainability, noting how Native architecture adapts to harsh climates in environmentally mindful ways.

“Whether it’s the way water moves around structures or how a hogan—a traditional dwelling and ceremonial structure—retains heat, these hold incredible value in my engineering work.”

Bagola, an integrative physiology student and a member of the Navajo (Diné) and Cheyenne River Sioux tribes, finds similar connections in her field.

“For us, health is not just physical—it’s about mind, spirit, and experience,” she explained.

“Indigenous medicine, like using sweat lodges, plays an important role in healing. Staying connected with your spirit is essential to being truly healthy.”

Community and Advice for Indigenous STEM Students

“AISES is a really welcoming community for Native students here at CU,” Redhorse said. “It’s a safe space where we can connect, share and rejuvenate. Our meetings are open to anyone, you don’t have to be Native. We welcome anyone who wants to learn about our culture and support us.”

Campus Organizations and Community Resources

Like Bagola, Redhorse also said her involvement with AISES has helped her grow as a leader. Recently, she was invited to welcome the keynote speakers at ��ƷSM��ӰƬ’s Indigenous Peoples’ Day plenary event—a role she could not have imagined for herself as a first-year student.

Chantal Baca, academic services manager for the BOLD Center, has served as the AISES faculty advisor for the past academic year. She noted the inclusive community for Indigenous students and credits AISES’ executive student board and members over the last five years.

“The AISES chapter is a remarkable group of student leaders who embody the vision, achievement and STEM student success,” said Baca. “Their membership has made a significant impact in the College of Engineering and Applied Science.”

Student leaders offer heartfelt advice to Indigenous students interested in STEM.

“It’s OK to feel alone sometimes, but find your community, and don’t be afraid to ask for help,” said Bagola. “Joining AISES helped me step out of my comfort zone, gain confidence and start reaching out to my professors and others in my field.”

“In engineering, there were five women in a room of 50 students—and being Native added another layer,” said Redhorse. “But, I’d tell anyone in that position: keep going.”

“Our people are resilient, and if you push through and find your community, you’ll thrive.”

The American Indian Science and Engineering Society has recognized ��ƷSM��ӰƬ as a top college for Indigenous students in its 2024-2025 national rankings.

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Life in space from a ��ƷSM��ӰƬ alumna who has been there

Jeff Zehnder — Tue, 12 Nov 2024 18:53:33 +0000

Life in space from a ��ƷSM��ӰƬ alumna who has been there Jeff Zehnder Tue, 11/12/2024 - 11:53

Jeff Zehnder

Sarah Gillis (AeroEngr’17) is a lead space operations engineer and astronaut trainer at SpaceX with literal out-of-this-world experience.

The ��ƷSM��ӰƬ alumna recently returned from a five-day orbital mission aboard Polaris Dawn, which took astronauts further from Earth than any have traveled since the end of the Apollo program in 1972.

On Nov. 11, she spoke to students and community members in a special event at Fiske Planetarium.

A Boulder native, Gillis shared what life was like in space for the four-member crew and details of the science and engineering that brought them to orbit and safely home.

What it is like experiencing launch for the first time.

Intellectually, I had studied all the physical changes you go through going to space, but actually going through them is fascinating. For this one moment, you’re defying gravity as the rocket lifts off the pad and you start accelerating and accelerating. You get pushed into your seat. The Gs get to about 4.5. When you get to second engine cutoff and you’re just floating, you no longer have pressure pushing you into the seat — you have fluid in your face. You suddenly feel like when you’re a kid and you’re laying upside down off the bed.

There’s an adjustment period once you are in orbit.

Every crew member goes through this time on board where you’re adapting. The first two days are pretty hard in space. You’re figuring it out. You’re going through all the physiological changes. You have this brain fog; you have elevated fluid. You can have space motion sickness.

You’re probably not feeling your best, in all honesty. How you set up a timeline for crew members in space should account for that. You could not possibly have talked our crew into doing any less on our mission, but hindsight is definitely helpful, and it’s just a reality that it takes a bit of time for crew members to adapt.

Keep an eye on space while following your passions.

I always knew how unlikely it was to ever become an astronaut. The statistics are not in your favor right now at our point in human history. I do think that’s going to change in the very near future if SpaceX is successful in bringing Starship online. You go from having four people in a spacecraft to 100 people in a spacecraft. As you change those numbers, cost of access to space will go down, so the opportunities that will exist will look much different in next 10-15 years.

For me, knowing how unlikely it was, it was super important to find things I was genuinely interested in. That way, no matter what happening in life, I couldn’t be disappointed because I was doing things that were interesting and engaging and things I wanted to be pursuing. Follow your curiosity, and it will take you to extraordinary places.

The incredible complexity of designing a space suit from scratch.

It was about a 2.5-year development program where one day we would show up and we’d have the left shoulder rebuilt in a certain way. The next Monday we’d show up and they’d have a whole new elbow for us to try. Then we’d go and get in the simulator and understand what worked and what didn’t and really fed that into the design process of these suits. It was a pretty extraordinary development effort.

There were times that we were learning stuff that went against industry knowledge. One of the things we discovered pretty late was the risk of electrostatic discharge in the suits. That led to an entire deep dive into understanding material testing.

One of the last tests we did still on Earth was once the suit had gone through all sorts of iterations, we actually took them to a vacuum chamber at Johnson Space Center and we wore them in the vacuum chamber and ran through the entire depress and repress sequence. It was just an extraordinary test of competence into the suit, understanding what the pressure changes and temperature changes would feel like.

Moving in space without gravity to weigh you down creates challenges.

What’s so cool about moving in a pressurized suit is it’s really almost physical problem solving. You can only rotate your shoulder so many degrees, or you can only extend your arm so far in the suit. What that means is you have to make sure that a person of a certain stature can perform everything they need to in that pressurized environment. It was a really cool development process with SpaceX to figure out what new mobility aids we needed in the spacecraft. What additional handholds and footholds would be required to make sure we could accomplish all the tasks we needed to.

On flight day two we got pressurized in the suits and did a dry run (of the spacewalk). It was really fun to actually see how things worked, and what were the things we hadn’t accounted for. As soon as I went to the controls and interfaced with them, based on where my center of mass was, my feet would suddenly start rotating up, and so I had to find a whole new strategy for how to secure myself when I was at the displays and how to transition out from the displays.

Train for the worst day so you can experience the best day.

In training we had really prepared for every possible scenario we could come up with for the EVA (extravehicular activity). Really as much as we could use the imagination to prepare bad day scenarios, we had trained for them, and it was so smooth. You train for the worst day so you can actually experience the best day. The spacewalk went exactly as we had hoped.

There is so much we do not know about life in space.

We partnered with 31 institutions on 36 research experiments, a lot of which came from CU, which I was really excited about. Some of my former professors actually contributed experiments to the mission.

Overall, the research was really focused on experiments that needed human involvement, things that could benefit future life as we try and look toward Mars. There’s a lot of health issues that astronauts encounter over long duration, and this includes space motion sickness, and spaceflight associated neuro-ocular syndrome.

Many astronauts do have degraded vision over time, and we don’t actually understand the mechanism at this point. It’s often associated with the fluid shift that happens where you suddenly have more fluid in your brain, but if we’re going to actually mitigate that and fix it in the future, we need to get to the heart of the cause, so we did a whole slew of experiments looking at different eye pressure and vision change data.

Re-entry is awesome.

It’s so, so cool to reenter Earth’s atmosphere. We start seeing a glow around the spacecraft at around 100 km. Then as you start to get lower you start to see these neon colors, pinks and oranges, and you actually see some of the sparks flying past the window. As you get lower in the atmosphere you start encountering turbulence with the different layers of the atmosphere. The thrusters are firing all around and it really feels like Dragon is clawing its way back into the atmosphere.

The mission does not end at splashdown.

We were picked up by the recovery vessel, and about 30 minutes later we climbed out of the spacecraft. We were checked out by the doctors before being flown by helicopter back to Kennedy Space Center, where we met our families. From there the mission wasn’t over, we had about a week of science and research and data collection post flight. We traveled to Houston pretty immediately for some high-density bone scans.

Trusting others with your life — teamwork is critical.

Human spaceflight is the ultimate team sport. It’s not only you have to have an extreme working relationship with the people on that mission — you are absolutely trusting them with your life to keep you safe. That extends to the people on the ground team as well, you have this entire team supporting you, and even more people behind the scenes beyond that.

As a trainer, I knew the technical side of Dragon and what you need to do to live and work in space, and what I found most interesting was in one of our early sims, the four of us go in the spacecraft, and we did terribly. We completely messed up the scenario. We were all going in different directions, chasing rabbit holes and ultimately just failed the simulation in so many ways. You have to learn how to work as a team.

It doesn’t matter what you bring to the team, you have to learn when to lead, when to follow, how you bring what you can contribute through a different lens because ultimately the success of the crew is what’s most important versus your own knowledge.

Seeing Earth from space changes you.

Seeing the Earth from that perspective cannot not change someone. All of our time here on Earth is so precious, your life is only so many hours overall. I have this immense appreciation for maximizing what we are here to do in this world. I think you certainly take calculated risks when you put yourself on a rocket and launch to space, or reenter the atmosphere. Those are all things that you have to believe that the risk is worth it for the benefit. It’s shifted my perspective a little bit on how cherished our time is with our family and our friends and what we’re here to do on this Earth. I’m still reflecting on it. I think it will continue to change me.

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Aerospace Engineering

Aircrafts of the future: Boosting aerodynamic performance by engineered surface vibrations

MURI Partners

Phononic Subsurfaces

Turbulence and Fuel Economy

2015 to Today

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Advancing real-time data compression for supercomputer research

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��ƷSM����ӰƬ among top colleges for Indigenous students

Indigenous Knowledge and STEM

Community and Advice for Indigenous STEM Students

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Life in space from a ��ƷSM����ӰƬ alumna who has been there

What it is like experiencing launch for the first time.

There’s an adjustment period once you are in orbit.

Keep an eye on space while following your passions.

The incredible complexity of designing a space suit from scratch.

Moving in space without gravity to weigh you down creates challenges.

Train for the worst day so you can experience the best day.

There is so much we do not know about life in space.

Re-entry is awesome.

The mission does not end at splashdown.

Trusting others with your life — teamwork is critical.

Seeing Earth from space changes you.

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��ƷSM��ӰƬ among top colleges for Indigenous students

Life in space from a ��ƷSM��ӰƬ alumna who has been there