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Published August 7, 2019 | public
Journal Article

Boolean logic by convective obstacle flows

Abstract

We present a potential new mode of natural computing in which simple, heat-driven fluid flows perform Boolean logic operations. The system comprises a two-dimensional single-phase fluid that is heated from below and cooled from above, with two obstacles placed on the horizontal mid-plane. The obstacles remove all vertical momentum that flows into them. The horizontal momentum extraction of the obstacles is controlled in a binary fashion, and constitutes the 2-bit input. The output of the system is a thresholded measure of the energy extracted by the obstacles. Due to the existence of multiple attractors in the phase space of this system, the input–output relationships are equivalent to those of the OR, XOR or NAND gates, depending on the threshold and obstacle separation. The ability to reproduce these logical operations suggests that convective flows might have the potential to perform more general computations, despite the fact that they do not involve electronics, chemistry or multiple fluid phases.

Additional Information

© 2019 The Author(s). Published by the Royal Society. Manuscript received 28/03/2019; Manuscript accepted 16/07/2019; Published online 14/08/2019; Published in print 08/2019. Data accessibility: The simulation code for generating all results can be found in the electronic supplementary material. Authors' contributions: S.J.B. first noticed that convective systems might have computational abilities, he wrote the code for the simulations, analysed the results and wrote the paper. Y.L.Y. provided guidance and advice. We declare we have no competing interests. This work was supported by the Caltech Division of Geological and Planetary Sciences Discovery Fund. Y.L.Y. was supported in part by an NAI Virtual Planetary Laboratory grant from the University of Washington to the Jet Propulsion Laboratory and California Institute of Technology.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023