Articles tagged with "fluid-dynamics"
Photos: NASA aces first flight reactor cold-flow tests since 1960s for deep space travel
NASA has successfully completed its first cold-flow test campaign since the 1960s for a flight reactor engineering development unit, marking a significant advancement in nuclear propulsion and power technologies critical for deep space exploration. Conducted at the Marshall Space Flight Center, these tests involved over 100 runs on a full-scale, non-nuclear test article built by BWX Technologies, simulating propellant flow under various operational conditions. The data gathered helps engineers understand fluid dynamics and reactor stability, confirming the design’s resistance to flow-induced oscillations and vibrations, which are vital for mission safety. This milestone results from a multi-year collaboration between NASA and industry partners aimed at developing flight-capable nuclear propulsion systems. Nuclear technology promises faster travel times, increased payload capacity, and enhanced communication capabilities, enabling more complex and data-intensive missions to the Moon, Mars, and beyond. The successful testing campaign provides essential technical data required to transition the technology from development toward practical application, supporting NASA’s long-term goals for sustained human and scientific exploration
energynuclear-propulsionspace-technologyNASAreactor-testingdeep-space-travelfluid-dynamicsVideo: NYU invents water-driven gears for machines that resist wear
Engineers at New York University have developed an innovative gear mechanism that uses fluid dynamics instead of traditional interlocking teeth to transmit motion. This new design replaces the conventional solid gear teeth, which have been used for thousands of years, with precisely directed fluid flows that engage without physical contact. Experiments involving cylinders submerged in a water-glycerol mixture demonstrated that the fluid can mimic gear teeth behavior by either pushing a second cylinder to spin in the opposite direction when close or pulling it along in the same direction when farther apart. This fluid-based approach allows for control over rotation speed and direction in ways not possible with mechanical gears. The fluid-driven gears offer significant advantages over standard gears, which are prone to jamming, breaking, or failing due to misalignment or debris. Since the fluid gears do not involve direct contact between parts, they are resistant to damage from grit or imperfections, as the fluid simply flows around obstacles. This durability and flexibility make them promising for applications such as soft robotics, where replacing hard metal
materialsmechanical-engineeringfluid-dynamicsgear-technologywear-resistancemachine-componentsNYU-researchPhysics-defying oil droplets hover, move against liquid flow in a first
Scientists at the Technical University of Darmstadt in Germany have, for the first time, observed microscopic oil droplets hovering and moving upstream against a flowing liquid, defying conventional fluid dynamics. Using the Ouzo effect—where mixing alcohol-oil solutions with water creates tiny oil droplets without surfactants—the team injected this mixture into a narrow flow channel and recorded the droplets’ behavior with high-speed cameras. They found that droplets could resist flow, remain stationary, or even move against the current due to differences in surface tension at their upper and lower ends, a phenomenon driven by Marangoni stresses in multi-component liquid mixtures. Although this effect occurs at microscopic scales under controlled conditions, the researchers suggest it may also manifest at larger scales, such as in emulsions containing numerous oil droplets, potentially leading to complex pattern formations. This discovery holds promise for applications in process engineering, microfluidics, and analytical chemistry, particularly for selectively trapping or extracting tiny droplets or bubbles from flowing liquids. The findings, funded by the
materialsmicrofluidicsfluid-dynamicssurface-tensionemulsionsanalytical-chemistryprocess-engineeringWorld’s fastest supercomputer runs record-breaking fluid simulation for rocket testing
Researchers at Lawrence Livermore National Laboratory (LLNL) have leveraged the exascale supercomputer El Capitan to perform the largest-ever fluid dynamics simulation, surpassing one quadrillion degrees of freedom in a single computational fluid dynamics (CFD) problem. The simulation modeled turbulent rocket exhaust flows from multiple engines firing simultaneously, a scenario relevant to modern rocket designs like SpaceX’s Super Heavy booster. Using a novel shock-regularization technique called Information Geometric Regularization (IGR), developed by a team including professors from Georgia Tech and NYU, the researchers achieved an 80-fold speedup over previous methods, reduced memory usage by 25 times, and cut energy consumption by more than five times. The simulation utilized all 11,136 nodes and over 44,500 AMD Instinct MI300A Accelerated Processing Units on El Capitan, and was extended on Oak Ridge National Laboratory’s Frontier supercomputer. This breakthrough sets a new benchmark for exascale CFD performance and memory efficiency
energysupercomputerfluid-dynamicsrocket-simulationhigh-performance-computingcomputational-fluid-dynamicsenergy-efficiencyRobotic zebrafish shows how fish brains use vision to swim in flowing water
A collaborative study by EPFL’s BioRobotics Lab and Duke University has demonstrated that visual cues alone enable larval zebrafish to maintain their position in flowing water. By combining realistic neural network models derived from live imaging of zebrafish brains with detailed simulations of visual processing, spinal connections, and swimming reflexes, the researchers successfully replicated the fish’s optomotor response—the automatic swimming behavior that counters water currents. This approach, which integrates brain circuits, body mechanics, and environmental factors, highlights the importance of studying brain function in the context of an animal’s physical form and natural surroundings, rather than in isolation. To validate their simulation, the team built an 80-centimeter robotic zebrafish larva equipped with cameras as eyes and motors for its tail, controlled by the same neural circuits as the simulation. When placed in a natural river environment, the robot was able to hold its position against the current, mirroring real zebrafish behavior. The study also uncovered that a small portion
roboticsbioinspired-robotsrobotic-zebrafishneurosciencebrain-simulationfluid-dynamicsoptomotor-responseSpace-time method unlocks unprecedented accuracy in fluid dynamics
Researchers at Rice University and Waseda University have advanced computational fluid dynamics (CFD) by developing a space-time computational flow analysis method that significantly improves accuracy in modeling complex fluid flows. Originally introduced by Tayfun Tezduyar in 1990, this approach integrates spatial and temporal dimensions of fluid flow simultaneously, unlike traditional methods that treat them separately. This unified representation allows for high-fidelity simulations that capture intricate, time-dependent flow patterns with unprecedented precision, enabling solutions to problems previously considered intractable. The method has been successfully applied across diverse fields including aerospace, medicine, automotive, and renewable energy. Notably, NASA used it to design reliable parachutes for the Orion spacecraft, while medical researchers employed it to simulate blood flow through heart valves, aiding cardiovascular surgeries. Automotive tire manufacturers analyze aerodynamics and cooling, and renewable energy experts assess turbulent wakes of wind turbines to optimize placement and reduce risks to aircraft and wildlife. By placing dense computational points in critical flow regions, the technique avoids accuracy losses
energyrenewable-energyfluid-dynamicscomputational-fluid-dynamicswind-turbinesaerospace-engineeringsimulation-methodsCentury-old turbulence theory confirmed in bubble swarm experiments
An international research team from Helmholtz-Zentrum Dresden-Rossendorf, Johns Hopkins University, and Duke University has experimentally confirmed a century-old turbulence theory proposed by Soviet mathematician Andrey Kolmogorov in 1941. Kolmogorov’s theory, known as K41 scaling, describes how energy cascades from large to small scales in turbulent flows. Using advanced 3D Lagrangian tracking and high-speed cameras capturing bubble swarms rising in a water column, the researchers provided the first direct evidence that bubble-induced turbulence follows Kolmogorov scaling at small scales, particularly for eddies smaller than the bubbles themselves. The experiments involved varying bubble sizes (3-5 mm) and gas densities in a controlled vertical water column, revealing that turbulence outside the immediate wakes of bubbles adheres closely to Kolmogorov’s predictions. The wakes themselves disrupt the flow structure, explaining why previous studies failed to detect this scaling in bubbly flows. The team also developed a new formula to estimate energy
energyturbulencefluid-dynamicsKolmogorov-scalingbubble-swarmexperimental-physicsenergy-cascadeRaindrops at rocket speeds: Water's impact on hypersonic craft revealed
A recent study has revealed how tiny water droplets, such as raindrops, can significantly affect hypersonic vehicles traveling at speeds exceeding Mach 5 (over 6,173 km/h). When these droplets impact a hypersonic aircraft or missile, they tend to break up into smaller droplets that become entrapped and accelerate near the vehicle’s surface. This interaction can disrupt the airflow around the vehicle and increase the likelihood of droplet impacts, especially with larger droplets, potentially affecting the vehicle’s structural integrity. The research team used advanced simulations combining Eulerian and Lagrangian frameworks to model the complex multiphase flow interactions between water droplets and hypersonic airflows. Their findings emphasize the importance of considering droplet breakup dynamics when estimating impact forces on hypersonic vehicles. This work not only aids in the design and development of next-generation hypersonic aircraft but also enhances the fundamental understanding of multiphase flows under extreme conditions. The researchers plan to conduct more detailed simulations to further explore individual
materialshypersonic-vehiclesfluid-dynamicsmultiphase-flowaerospace-engineeringsimulationdroplet-impactGermany's JUPITER becomes fourth fastest supercomputer in the world
Germany’s JUPITER supercomputer, located at the Jülich Supercomputing Centre (JSC), has become the fourth fastest supercomputer globally and the fastest in Europe. This achievement was supported by a collaboration with Georgia Tech, where Assistant Professor Spencer Bryngelson accessed JUPITER through the JUPITER Research and Early Access Program (JUREAP). Bryngelson’s Multi-Component Flow Code (MFC) was tested on JUPITER to study the behavior of droplets subjected to high-velocity shockwaves, a complex fluid dynamics problem with significant engineering implications, especially for supersonic and hypersonic aerospace applications. The simulations revealed how droplets deform and break apart under shockwaves, providing valuable insights that help reduce risks and costs associated with physical testing. The MFC project, part of the broader Exascale Multiphysics Flows (ExaMFlow) collaboration between Georgia Tech and JSC, demonstrated strong performance on JUPITER’s key components—the JUWELS
energysupercomputinghigh-performance-computingsimulationsaerospace-engineeringfluid-dynamicsexascale-computing