@article{14754,
  abstract     = {The large-scale laminar/turbulent spiral patterns that appear in the linearly unstable regime of counter-rotating Taylor–Couette flow are investigated from a statistical perspective by means of direct numerical simulation. Unlike the vast majority of previous numerical studies, we analyse the flow in periodic parallelogram-annular domains, following a coordinate change that aligns one of the parallelogram sides with the spiral pattern. The domain size, shape and spatial resolution have been varied and the results compared with those in a sufficiently large computational orthogonal domain with natural axial and azimuthal periodicity. We find that a minimal parallelogram of the right tilt significantly reduces the computational cost without notably compromising the statistical properties of the supercritical turbulent spiral. Its mean structure, obtained from extremely long time integrations in a co-rotating reference frame using the method of slices, bears remarkable similarity with the turbulent stripes observed in plane Couette flow, the centrifugal instability playing only a secondary role.},
  author       = {Wang, B. and Mellibovsky, F. and Ayats López, Roger and Deguchi, K. and Meseguer, A.},
  issn         = {1471-2962},
  journal      = {Philosophical Transactions of the Royal Society A},
  keywords     = {General Physics and Astronomy, General Engineering, General Mathematics},
  number       = {2246},
  publisher    = {The Royal Society},
  title        = {{Mean structure of the supercritical turbulent spiral in Taylor–Couette flow}},
  doi          = {10.1098/rsta.2022.0112},
  volume       = {381},
  year         = {2023},
}

@article{9166,
  abstract     = {Light-activated self-propelled colloids are synthesized and their active motion is studied using optical microscopy. We propose a versatile route using different photoactive materials, and demonstrate a multiwavelength activation and propulsion. Thanks to the photoelectrochemical properties of two semiconductor materials (α-Fe2O3 and TiO2), a light with an energy higher than the bandgap triggers the reaction of decomposition of hydrogen peroxide and produces a chemical cloud around the particle. It induces a phoretic attraction with neighbouring colloids as well as an osmotic self-propulsion of the particle on the substrate. We use these mechanisms to form colloidal cargos as well as self-propelled particles where the light-activated component is embedded into a dielectric sphere. The particles are self-propelled along a direction otherwise randomized by thermal fluctuations, and exhibit a persistent random walk. For sufficient surface density, the particles spontaneously form ‘living crystals’ which are mobile, break apart and reform. Steering the particle with an external magnetic field, we show that the formation of the dense phase results from the collisions heads-on of the particles. This effect is intrinsically non-equilibrium and a novel principle of organization for systems without detailed balance. Engineering families of particles self-propelled by different wavelength demonstrate a good understanding of both the physics and the chemistry behind the system and points to a general route for designing new families of self-propelled particles.},
  author       = {Palacci, Jérémie A and Sacanna, S. and Kim, S.-H. and Yi, G.-R. and Pine, D. J. and Chaikin, P. M.},
  issn         = {1471-2962},
  journal      = {Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences},
  keywords     = {General Engineering, General Physics and Astronomy, General Mathematics},
  number       = {2029},
  publisher    = {The Royal Society},
  title        = {{Light-activated self-propelled colloids}},
  doi          = {10.1098/rsta.2013.0372},
  volume       = {372},
  year         = {2014},
}