The Dryden Drop Tower is a six-story research facility in the center atrium of Portland State University’s Engineering Building. The tower allows students and researchers to study how fluids, materials, and prototypes behave in short-duration microgravity.

Objects released in the tower experience a fall of approximately 100 feet and about 2.1 seconds of weightlessness, creating a controlled environment for experiments that are difficult or impossible to conduct under normal gravity conditions.

Facility Capabilities

The tower stands approximately 31 meters tall, with a free-fall distance of about 22.2 meters. A drag shield helps reduce the effects of aerodynamic drag during free fall, allowing experiments to achieve microgravity levels of approximately 2×10−4g2 \times 10^{-4} g2×10−4g.

The facility can support up to 80 drops per day. Experiments are operated by push-button control from a single station, with full wireless CCTV coverage. Payloads are safely decelerated using passive magnetic braking.

Research Focus

The Dryden Drop Tower is part of the Wind Energy and Turbulence Lab, which studies fluid behavior in turbulent regimes. The lab’s research includes flows related to:

  • Wind energy
  • Volcanic eruptions
  • Forest canopies
  • Capillary fluidics
  • Droplet and bubble behavior
  • Contact line dynamics

By scaling and studying these flows in controlled environments, researchers can better understand how fluids interact with natural and engineered systems.

Microgravity Research

The tower supports capillary fluidics research by allowing researchers to study capillary-driven flows at larger length scales than are possible on the ground. Experiments conducted in the Dryden Drop Tower have explored droplet ejection, bubble behavior, and contact line dynamics.

Research conducted using the tower has also contributed to experiments later performed aboard the International Space Station.

History

The Dryden Drop Tower was completed in 2010 with donor support in honor of Robert Dryden, who served as dean of the Maseeh College of Engineering and Computer Science for 13 years, until 2008.

The Engineering Building atrium was originally designed with space for the tower, but construction was not completed until donor funding made the project possible.

Student Opportunities

Student research opportunities in this lab are available as part of our Undergraduate Research and Mentoring Program.

Learn more about solar energy research and wind energy research at PSU.