National Advanced Air Mobility Industry Forum (NAAMIF)
We’re excited to be heading to Springfield, Ohio in October, for the 2026 National Advanced Air Mobility Industry Forum(NAAMIF)! Bringing together manufacturers, suppliers, innovators, and industry leaders from across the AAM ecosystem, the forum is a great opportunity to explore where the future of flight is headed—from emerging technologies and infrastructure to the practical challenges of bringing new aircraft and mobility solutions to market. With TotalSim’s continued work across aerospace and advanced simulation, we’re looking forward to connecting with the people and ideas helping move the industry forward.
47G Zero Gravity Summit
Later this fall, we’ll also be heading to Salt Lake City for 47G's Zero Gravity Summit. The event brings together leaders working across aerospace, defense, dual-use technology, national security, space, energy, and other emerging technology sectors. For us, it’s an exciting opportunity to connect with organizations tackling some of today’s biggest technical challenges and to see how advanced engineering, simulation, autonomy, and innovation are continuing to shape what comes next. We’re looking forward to joining the conversation!
Optimizing Tennis Racket
Aerodynamics and Spin with CFD
In modern tennis, the difference between a good shot and a great one often comes down to two things: how fast a player can swing the racket and how much topspin they can generate. Designing equipment that improves both is a classic engineering challenge—more open string beds can reduce drag, but the same geometry must still deliver the friction and dwell time needed for heavy spin. TotalSim applied its Siemens Star-CCM+ workflows to this problem, drawing on methods refined in motorsports and cycling aerodynamics. The team modeled a modern mid-plus racket and systematically tested the influence of string pattern density and frame-edge geometry.
The team compared two string patterns: a more open 16×19 and a denser 18×20. Frame edges were also varied between a conventional rounded profile and a more aggressive beveled design. Simulations covered both the steady airflow during a typical swing and the transient interaction when the ball meets the strings.
Key results
Open string patterns allowed significantly more air to pass through the racket face, cutting aerodynamic drag by roughly 12–18 percent compared with denser patterns.
Beveled frame edges combined with carefully spaced strings near the sweet spot improved predicted topspin rates by approximately 10–12 percent.
The stronger spin increased the Magnus force on the ball, producing steeper trajectories and greater net clearance for a given launch angle.
CFD visualization of the Magnus effect on a tennis ball—showing how topspin and backspin change the surrounding airflow and resulting trajectory.
String Theory in action
These findings give racket designers concrete levers. String density primarily governs drag and swing speed, while frame bevels and local string spacing strongly influence spin generation. Because the work was performed entirely in simulation, multiple design variants could be evaluated quickly and cost-effectively—long before physical prototypes were built. Traditional development still relies heavily on player testing and limited wind-tunnel data. CFD does not replace those steps, but it dramatically reduces the number of physical iterations required and provides far richer insight into why one design outperforms another.
Summary
Using Siemens Star-CCM+, TotalSim quantified how string pattern density and frame-edge geometry affect both aerodynamic drag and spin generation on a tennis racket. Open string patterns reduced drag by 12–18 %, supporting higher swing speeds, while optimized bevels and string spacing improved predicted topspin by roughly 10–12 %. The study demonstrates how CFD can deliver actionable design insight for sports equipment—faster and with greater clarity than traditional physical testing alone.
Siemens Simcenter Radioss:
High-Speed Explicit Simulation
for Crash, Impact, and Extreme Events
Radioss crash model setup—typical of the explicit dynamics workflows
used for vehicle impact and safety analysis.
While TotalSim is best known for high-fidelity CFD across automotive, motorsports, aerospace, marine, and consumer products, many of the same clients also face challenges that CFD alone cannot fully address: crash and impact events, drop testing, and extreme nonlinear deformation. That’s where Altair Radioss (and its open-source counterpart, OpenRadioss) comes in. Radioss is a leading high-speed explicit finite-element solver designed for highly nonlinear dynamic problems. It handles the rapid, large-deformation scenarios that occur in milliseconds—vehicle crash, bird strike, battery pack integrity under impact, drop tests of electronics or sports equipment, and blast or high-velocity events. Radioss has a long track record in automotive safety, aerospace structural integrity, and consumer-goods durability. OpenRadioss, released as open source by Altair, shares the same core technology and input formats while inviting community-driven development. Both versions excel at capturing complex material failure, contact, and multiphysics interactions under sudden loading.
What is Simcenter Radioss? Simcenter Radioss is Siemens’ branding of the industry-proven explicit finite-element solver for highly nonlinear dynamic problems. It is the same core technology as Altair Radioss, delivered within the Siemens Simcenter portfolio. The solver is designed for events that happen in milliseconds—crash, impact, blast, bird strike, drop tests, and extreme deformation—where traditional implicit solvers struggle.
Key strengths include:
Accurate modeling of complex material failure, contact, and large deformations
Strong scalability for large models
Ability to run many industry-standard input formats (including LS-DYNA decks in many cases)
Availability as both a commercial solution (Altair Radioss / Simcenter Radioss) and an open-source version (OpenRadioss)
OpenRadioss shares the same fundamental technology and input formats while enabling community-driven development and broader access for research and early-stage work. Radioss has a long track record in automotive safety, aerospace structural integrity, and consumer-goods durability. Both the commercial and open-source versions excel at capturing complex material failure, contact, and multiphysics interactions under sudden loading.
How it connects to TotalSim’s clients and projects
For TotalSim’s typical clients, this capability is complementary rather than competitive:
Aerospace and defense teams already using CFD for external aerodynamics or internal flows often need reliable crash and bird-strike analysis.
Automotive and motorsports groups optimizing vehicle or component aero performance also require crashworthiness and safety validation.
Consumer-goods and electronics manufacturers who come for thermal or airflow simulation frequently need drop-test and impact durability studies.
Marine and energy applications likewise benefit from impact and fluid-structure interaction modeling.
Real Benefits for Engineers
Because Radioss sits within the broader Altair and Siemens ecosystems (available as Simcenter Radioss), it integrates naturally with the tools many clients already use. Engineers can explore design variants for both aerodynamic efficiency and structural robustness within a consistent digital workflow—reducing the number of physical prototypes and accelerating time to market. Whether the challenge is a full-vehicle crash, a battery enclosure under side impact, a composite structure under high-velocity strike, or a consumer product surviving repeated drops, explicit solvers like Radioss deliver the insight needed for safer, more resilient designs.
Access and Support Through TotalSim US
With the integration of Altair into Siemens, TotalSim US is now positioned to sell, support, and train engineers on Simcenter Radioss as well as the broader combined portfolio of CAE tools from Siemens and Altair . This expanded capability provides customers with expert guidance and seamless support across the full range of industry-leading simulation technologies.
Conclusion
CFD and explicit dynamics together give a more complete picture. TotalSim helps clients choose and apply the right combination of tools so that performance, safety, and durability are addressed in parallel rather than in sequence.
RD-E: 4900 Bird Strike on Windshield
And One More Thing...Eric Jacuzzi
We were referenced by Eric Jacuzzi, the outgoing NASCAR VP of Vehicle Performance, in the August edition of Racecar Engineering. We will provide information about the article in our quarterly newsletter next month. Here is what he had to say:
"The final question of whether the revised package would result in greater ability to pass was the hardest one of all to determine. Working with NASCAR’s CFD partner, TotalSim USA, a two-car passing manoeuvre was completed in STAR-CCM+. Reviewing race footage, a pass was observed by Tyler Reddick that showed an approximately 5mph delta between leading and trailing car, as well as the motion path he took to complete it. In the CFD model, the trailing car was then prescribed this same motion and closing rate. The simulation was extremely challenging due to the sliding mesh, domain size, and the need to save video periodically, taking over 10 days to solve for each run. The results showed that the balance of forces between aerodynamic drag and engine power was three times more favourable with the four-inch spoiler than the seven-inch spoiler package, indicating a higher likelihood to complete the pass".
Eric, thank you for all the amazing work we got to do with you. The TotalSim team.
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