This discovery fundamentally redefines how scientists understand the mechanical response of liquids. While viscosity has long been acknowledged as a measure of a fluid’s resistance to flow, its role in governing the structural robustness of liquids under extreme deformation had not been fully appreciated until now. The implications span far beyond academic curiosity, offering potential insights for diverse applications ranging from advanced hydrodynamic systems and additive manufacturing technologies like 3D printing, to biomedical engineering disciplines concerned with fluid behavior in physiological contexts such as blood vessels.

Dr. Thamires Lima, an assistant research professor at Drexel’s College of Engineering and a lead author on the study, explained, “Our experiments reveal that when a simple liquid is pulled apart with sufficiently high force per unit area, it reaches a critical stress threshold at which it fractures much like a solid. Contrary to longstanding assumptions, this solidlike fracture is not limited to complex or elastic fluids but appears to be a fundamental property of all simple liquids—including common ones like water and oil.”

This unexpected fracture phenomenon was first noticed during extensional rheology tests involving viscous, tar-like hydrocarbon blends in collaboration with ExxonMobil Technology & Engineering Company. Extensional rheology, which explores how fluids deform under stretching rather than shear, typically reveals a gradual thinning and eventual breakup in fluids such as honey or syrup. However, instead of this continuous deformation, the hydrocarbon mixtures suddenly snapped with an audible crack, much like a brittle solid. The research team initially doubted their observation and conducted multiple repetitions to validate the authenticity of the fracture event.

By deploying high-speed imaging, the researchers captured the fracturing dynamics, observing the fluid elongating until reaching a critical stress point, then rapidly snapping apart in an instantaneous event. Such brittle fracture is a hallmark of solids under tensile stress but was previously unknown for simple viscous liquids. The magnitude of the critical stress measured was approximately 2 megaPascals, comparable to the force experienced if a laundry bag full of bricks were suddenly tugged to its breaking point.

Intriguingly, subsequent experiments using a chemically distinct simple liquid, styrene oligomer—carefully matched in viscosity to the hydrocarbon blends—yielded similar results, cracking under identical stretching rates. This consistency strongly suggests that the breaking point is governed by viscosity-dependent stress rather than specific chemical composition. The team further reinforced this conclusion by varying the temperature of the liquids, thereby modulating their viscosity. Across these conditions, each fluid exhibited fracturing behavior only at specific stretching rates corresponding to the same critical stress value.

This paradigm shift calls into question the traditional notion that fracture is a mechanical response exclusively linked to elasticity—the ability of materials to store and release energy under deformation. Simple liquids, lacking intrinsic elastic storage mechanisms above their glass transition temperatures, were long believed incapable of such abrupt failure. Yet, this research decisively demonstrates that viscous effects alone can induce fracture, indicating a previously unrecognized solidlike behavior in fluids traditionally categorized as purely flowing substances.

Comparative testing between the simple fluid oligomer styrene and its polymeric counterpart further revealed that both materials fractured at closely matching critical stress values. This outcome is particularly telling, as it underscores that elasticity, which is more pronounced in polymeric fluids, may not be a determining factor in the fracture phenomenon. Instead, the results point towards a universal mechanism based primarily on the viscous and stress-dependent nature of the liquids.

The researchers hypothesize that the fracturing process might be linked to cavitation—a phenomenon involving the nucleation, growth, and collapse of vapor cavities or bubbles under tensile stress within the fluid. Such rapid implosions can produce shock waves that propagate through the liquid, potentially triggering brittle fracture-like failure. However, this mechanism remains speculative and invites further experimental and theoretical scrutiny.

Looking ahead, Dr. Lima and her colleagues intend to deepen their investigation into the microscopic and molecular origins of this solidlike fracture. Understanding the physics that govern the transition from continuous fluid deformation to sudden rupture will be key to exploiting these effects in practical applications. From improving the control of viscous liquid fibers in industrial spinning processes to enhancing the durability of fluidic systems in manufacturing and medicine, this newfound knowledge opens a rich frontier for engineering innovation.

The significance of this discovery resonates throughout the scientific community, as it challenges fundamental concepts taught in fluid dynamics and materials science. It beckons a reconsideration of long-held models and heralds a new era where the mechanical behavior of fluids can no longer be dichotomously classified as either solid or liquid, but rather understood on a spectrum where viscous fluids can behave like solids under critical conditions.

By shedding light on the intrinsic capacity of simple liquids to withstand and succumb to mechanical stresses akin to solids, this study forges a bridge between two classical states of matter, enriching our comprehension of the natural world and inspiring future technological advancements grounded in this novel insight.

Subject of Research: Not applicable

Article Title: Unexpected solidlike fracture in simple liquids

News Publication Date: 26-Mar-2026

Web References:
10.1103/t2vy-32wr

Image Credits: Drexel University

Keywords

Fluid dynamics, Viscous liquids, Brittle fracture, Extensional rheology, Critical stress, Cavitation, Physical Review Letters, Material science, Mechanical properties, Simple liquids, Viscosity, Liquid fracture

The study primarily addresses the challenges faced in accurately predicting the behavior of complex fluid flows within medical devices. Blood pumps, essential for numerous medical applications, require precise fluid dynamics modeling to ensure efficiency and safety. Traditional computational fluid dynamics methods, particularly RANS, though widely utilized, often fall short in capturing the unsteady, turbulent nature of blood flow in real-time scenarios. This study advocates for the adoption of LES as a promising alternative, claiming that it can provide a more nuanced depiction of turbulence and flow separation that typically occurs in these devices.

To establish a robust framework for this study, the researchers undertook a meticulous experimental validation process. They meticulously designed and executed a set of controlled experiments, measuring the fluid flow patterns generated within a prototype blood pump. By utilizing advanced diagnostic tools such as Particle Image Velocimetry (PIV), they were able to capture high-fidelity velocity fields and turbulence characteristics. These measurements served as a benchmark for validating their LES models, offering unprecedented insights into the flow behaviors that occur in a magnetically levitated blood pump.

The findings of this research demonstrate a marked improvement in predictive accuracy when using LES models compared to RANS. The LES framework exhibited a superior ability to replicate the time-dependent flow structures and turbulence intensities observed in the experiments. This correlation emphasizes the importance of accurately simulating the complex interactions between blood and the pumping mechanism, which could potentially revolutionize the design and optimization of blood pumps in clinical settings.

Moreover, the research outlines the potential for adopting LES methodologies in other biomedical applications that require precise fluid dynamics modeling. The implications of this study extend beyond just the blood pump domain; numerous medical devices rely on accurate fluid flow simulations for operational efficiency and patient safety. The transition towards more advanced simulation techniques could lead to more sophisticated designs and improved outcomes in devices such as stents, heart valves, and other fluid transport technologies.

In evaluating the future of this technology, the authors suggest that an interdisciplinary approach, merging engineering, medicine, and computational sciences, is crucial. They advocate for collaborative research efforts, emphasizing the need for a synergy between experimental validation and computational modeling. The progression towards more refined and accurate predictive models will inevitably enhance our understanding of complex blood flow dynamics, contributing to the development of next-generation medical devices that are safer and more effective.

As advancements in computational power and algorithms continue to proliferate, the adoption of LES in the medical field will become more viable. The sophistication of these tools enables researchers to delve deeper into the nuances of fluid dynamics, analyzing intricate details that were previously beyond reach. This capability not only enriches our understanding but also paves the way for tailoring medical devices to meet the unique demands of individual patients, thus enhancing personalized medicine.

The researchers also highlight potential challenges in the implementation of LES in clinical practice. While the accuracy and depth of insights provided by LES are impressive, the computational resources and time required for simulation pose significant hurdles. As such, further technological advancements in computational efficiency will be essential to making these techniques accessible and viable for everyday use in medical device development.

In conclusion, the experimental validation of LES as a benchmark for RANS flow modeling represents a significant stride in the biomedical engineering field. The research conducted by Abeken, Gülan, and von Petersdorff-Campen not only underscores the importance of accurate fluid dynamics in blood pump technology but also highlights the broader implications for medical device development. As we move forward, embracing advanced modeling techniques such as LES may very well transform the landscape of biomedical engineering, offering new possibilities for improving patient care through innovative device design.

The impact of this study resonates with a broader community of researchers and innovators in the field of engineering and medicine. As academia and industry collaborate to harness these groundbreaking techniques, the potential for developing safer, more efficient biomedical devices will continue to grow. Ultimately, the synergistic fusion of experimental validation and computational modeling stands as a beacon of hope for the future of medical technology, promising advancements that could profoundly alter the treatment landscape.

The research underscores a critical narrative in the evolution of biomedical engineering: continuous improvement through scientific inquiry, interdisciplinary collaboration, and the integration of advanced computational methods will lead to a brighter future for medical device innovation. In reflecting upon the findings and implications of this study, the scientific community is called to action – to embrace these advancements not just as theoretical constructs but as a viable pathway to improve the lives of patients around the globe.

Subject of Research: Large Eddy Simulation in Blood Pumps

Article Title: Experimental Validation of Large Eddy Simulation as a Benchmark for Reynolds-Averaged Navier-Stokes Flow Modeling in a Magnetically Levitated Blood Pump.

Article References: Abeken, J., Gülan, U., von Petersdorff-Campen, K. et al. Experimental Validation of Large Eddy Simulation as a Benchmark for Reynolds-Averaged Navier-Stokes Flow Modeling in a Magnetically Levitated Blood Pump. Ann Biomed Eng (2025). https://doi.org/10.1007/s10439-025-03846-4

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s10439-025-03846-4

Keywords: Fluid Dynamics, Biomedical Engineering, Blood Pumps, Large Eddy Simulation, Reynolds-Averaged Navier-Stokes, Experimental Validation