Turbulence is one of the most complex and fascinating phenomenon in fluid dynamics. It governs the efficiency of energy transport in pipelines, affects the safety of air and space travel, and even influences climate systems. Researchers from King Abdullah University of Science and Technology (KAUST) are now advancing our understanding of fluid behavior under extreme turbulent conditions through an international collaboration.

At the Centre for International Cooperation in Long Pipe Experiments (CICLoPE) in Bologna, Italy, KAUST scientists—alongside colleagues from the University of Bologna, the German Aerospace Center (DLR), and partners in the United States  — are studying pipeline turbulence at scales rarely accessible in laboratory settings.

Why Study Turbulence in a Giant Pipe?

Pipelines are the backbone of modern industry, transporting oil, gas, chemicals, and water. Yet, frictional resistance within pipes causes pressure drops that require massive pumping power—pipeline transport alone consumes nearly 10% of global electricity. Understanding and mitigating turbulence could lead to energy savings on a global scale.

The CICLoPE facility, housed in an old WWII aircraft factory, features a 110-meter-long pipe with a 0.9-meter inner diameter, making it one of the largest and most advanced wind tunnel facilities of its kind. Its dimensions allow scientists to study fully developed turbulent flows at Reynolds numbers up to 3.5 million, producing insights directly relevant to industrial and natural systems.

Cutting-Edge Imaging Technology

The KAUST High-Speed Fluids Imaging Lab, led by Professor Siggi Thoroddsen, with his team, Drs. Krishna Raja, Abdullah Alhareth, Vivek Mugundhan and Andres Aguirre-Pablo, deployed Tomographic Particle Image Velocimetry (Tomo-PIV) to visualize turbulence in unprecedented detail. By seeding the air with micron-sized smoke particles and illuminating them with high-power pulsed lasers, provided by DLR Göttingen, the team captured the chaotic dance of eddies and vortices, at resolutions down to 18 micrometers.

Four synchronized high-speed cameras record the swirling flow, allowing researchers to compute 3D velocity fields, circulation, and energy dissipation rates, by tracking the motion of about 100,000 particles within a small volume. These measurements open doors to new findings on how turbulence transfers momentum and heat—key factors in designing more efficient energy and transport systems.

A Saudi-Led Global Effort

While the experiments are conducted in Italy, the project reflects Saudi Arabia’s Vision 2030 priorities in sustainability, aerospace, and ocean systems. Collaborations extend to King Abdulaziz City for Science and Technology (KACST), where team member Dr. Abdullah Alhareth bridges the academic and national research agendas.

External advisors include Professor Hassan Nagib (Illinois Institute of Technology) and KAUST Professor Peter Schmid who have guided theoretical and computational aspects of these studies at CYCLoPE.

The Road Ahead

The KAUST team has already captured 3D velocity fields near the pipe axis, and the next step is to extend measurements closer to the pipe walls, where turbulent boundary layers are most active. These findings will have impact not only industrial applications but also aerodynamics studies linked to the Future Mobility Sandbox, a joint initiative between KAUST and the Saudi Ministry of Transport and Logistics.

Reflecting on his research, Professor Thoroddsen cited Theodore von Kármán: Scientists discover the world that exists; engineers create the world that never was. Thoroddsen added, KAUST’s turbulence research exemplifies this spirit—combining scientific discovery with engineering innovation to shape a more sustainable future.