Experimental Physics · Fluid Metrology · Turbulence

Christopher JCrowley

Experimental physicist

I develop measurement techniques for characterizing fluid flow — from laser velocimetry and image-based analysis to acoustics — and study turbulence through the lens of dynamical systems.

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About

I'm Chris Crowley, an experimental physicist. I spend my time figuring out how to measure things that are hard to measure.

I take hard measurement problems from idea to working prototype — working out the theory, inventing a clever (often low-cost) approach, then building and testing the instrument. I've been at it for 15+ years, from primary flow standards at NIST to turbulence experiments at Georgia Tech and Johns Hopkins.

Two kinds of problems pull me in: cheap, clever measurement — a microcontroller and a few basic circuits standing in for an expensive instrument, once you've rethought the measurement itself — and making sense of complicated datasets, where the uncertainty analysis drives the choice of model. Either way, the goal is the same: the best measurement possible.

Christopher J Crowley
PhD
Physics, Georgia Tech
Builds
Instruments, circuits, demos
Likes
Cheap parts doing expensive jobs

Where I've been

Experience & education

Research experience

2023–now
Physicist
National Institute of Standards and Technology (NIST)
Airspeed and low-flow calibration standards, including a new ultra-low-speed primary standard and an optical-chopper method for calibrating laser Doppler anemometers.
2025–now
Adjunct Assistant Professor
Johns Hopkins University
Developed a novel time-of-flight image-velocimetry system for oceanic turbulence measurements.
2022–23
Postdoctoral Fellow
Johns Hopkins University
Designed and built a custom high-speed scanning dual stereo PIV–PLIF system for variable-density flow experiments.
2014–22
Graduate Research Assistant
Georgia Institute of Technology
Built a novel Taylor–Couette apparatus and an in-house time-resolved volumetric velocimetry system; first experimental evidence that turbulence tracks recurrent solutions (PNAS).
2007–13
Research Associate
National Institute of Standards and Technology (NIST)
Physical models and uncertainty analysis for primary flow standards; wind-tunnel experiments and calibrations of transfer standards.

Education

2022
PhD in Physics
Georgia Institute of Technology
Minor in Mechanical Engineering
2015
M.S. in Physics
Georgia Institute of Technology
2013
B.S. in Physics
University of Maryland
Minor in Philosophy

Research interests

Measuring — and taming — turbulent flow

My work has centered on two intertwined areas: fluid flow metrology and fluid turbulence. Studying how to improve flow measurement made clear that turbulence sits at the heart of nearly every metering challenge — and that the tools of chaos theory and dynamical systems may finally let us predict and control it.

01

Flow metrology at NIST

Maintaining primary flow standards and improving calibration — from uncertainty analysis and wind-tunnel experiments to establishing safer, non-toxic surrogate calibration fluids.

02

Turbulence as dynamics

Testing a dynamical-systems description of turbulence: special unstable solutions of the Navier–Stokes equations whose connections act as a road map for where a chaotic flow goes next.

03

Time-resolved tomo-PIV

A custom fully time-resolved tomographic Particle Image Velocimetry rig captures 3-D turbulent velocity fields in Taylor–Couette flow, compared against spectral Newton–Krylov simulations.

Selected work

Selected publications

A selection from 10 journal articles, 17 conference papers, and 3 NIST publications — see the full list on Google Scholar →

01
Calibrating laser Doppler anemometers utilizing an optical chopper
C. J. Crowley, I. I. Shinder, M. R. Moldover, et al.
Metrologia 62, 025001 · 2025
02
Turbulence tracks recurrent solutions
C. J. Crowley, J. Pughe-Sanford, W. Toler, R. O. Grigoriev, M. F. Schatz
Proceedings of the National Academy of Sciences 119 (34) · Aug 2022
03
C. J. Crowley, M. C. Krygier, D. Borrero-Echeverry, R. O. Grigoriev, M. F. Schatz
Journal of Fluid Mechanics 892, A12 · 2020
04
D. Borrero-Echeverry, C. J. Crowley, T. P. Riddick
Physics of Fluids 30, 087103 · Aug 2018
05
I. Uzelac, C. J. Crowley, S. Iravanian, T. Y. Kim, H. C. Cho, F. H. Fenton
Frontiers in Physiology 13 · Feb 2022

Off the clock

Projects & demos

I like simple, exciting demonstrations of physical principles — and I can't help running them like experiments. Each of these follows the same loop as my research: a question, a build, a measurement.

Resources

Tools & notes I've shared