Publications

S. Varchanis, “A Space-Time Galerkin/Least-Squares Method for the Simulation of non-Newtonian fluids,” to be submitted to Computer Methods in Applied Mechanics and Engineering, 2026.

S. Varchanis, “The persistence of stress singularities in Oldroyd-B fluids,” to be submitted to Physical Review Fluids, 2026.

U. Uršič, S. Varchanis, F. Decker, A. Kickuth, D. B. Stein, M. J. Shelley, J. Brugués, Robustness of geometry sensing: Centrosome positioning in early development across variable cytoplasmic conditions, In preparation, 2026.

S. Varchanis, U. Uršič, D. B. Stein, J. Brugués, M. J. Shelley, Deciphering the mechanobiological origins of aster decentering, In preparation, 2026.

S. Varchanis, U. Uršič, D. B. Stein, J. Brugués, M. J. Shelley, Asterology: The rheology of aster-like structures, In preparation, 2026.

F. Hillebrand, R. J. Hill, M. Davoodi, S. J. Haward, A. Q. Shen, R. J. Poole, and S. Varchanis, “Flat elastic disc suspensions are indistinguishable from solutions of long flexible polymers within planar incompressible flows, Physical Review Letters, vol. 135, Art. no. 024002, 2025. https://doi.org/10.1103/pmsq-b1th

A. Spyridakis, P. Moschopoulos, S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “Flow of a viscoelastic fluid around a confined cylinder: 2D linear stability analysis,” Journal of Fluid Mechanics, vol. 1001, Art. no. A40, 2024. https://doi.org/10.1017/jfm.2024.1113

S. Varchanis, E. Younes, S. J. Haward, and A. Q. Shen, “Emergence of lobed wakes during the sedimentation of spheres in viscoelastic fluids,” Journal of Fluid Mechanics, vol. 992, Art. no. A14, 2024. https://doi.org/10.1017/jfm.2024.459

F. Hillebrand, S. Varchanis, C. C. Hopkins, S. J. Haward, and A. Q. Shen, “Flow of wormlike micellar solutions over concavities,” Soft Matter, vol. 20, pp. 7133-7146, 2024. https://doi.org/10.1039/D4SM00594E

A. Spyridakis, P. Moschopoulos, S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “Thixo-elasto-viscoplastic modeling of human blood,” Journal of Rheology, vol. 68, pp. 1–23, 2024. https://doi.org/10.1122/8.0000711

A. Yokokoji, S. Varchanis, A. Q. Shen, and S. J. Haward, “Rheological effects on purely-elastic flow asymmetries in the cross-slot geometry,” Soft Matter, vol. 20, pp. 152–166, 2024. https://doi.org/10.1039/D3SM01209C

S. T. Chan, S. Varchanis, S. J. Haward, and A. Q. Shen, “Perspective on edge fracture,” Journal of Rheology, vol. 67, pp. 949–963, 2023. https://doi.org/10.1122/8.0000625

S. J. Haward, S. Varchanis, G. H. McKinley, M. A. Alves, and A. Q. Shen, “Extensional rheometry of mobile fluids. Part II: Comparison between the uniaxial, planar, and biaxial extensional rheology of dilute polymer solutions using numerically optimized stagnation point microfluidic devices,” Journal of Rheology, vol. 67, pp. 1011–1030, 2023. https://doi.org/10.1122/8.0000660

S. J. Haward, F. Pimenta, S. Varchanis, D. W. Carlson, K. Toda-Peters, M. A. Alves, and A. Q. Shen, “Extensional rheometry of mobile fluids. Part I: OUBER, an optimized uniaxial and biaxial extensional rheometer,” Journal of Rheology, vol. 67, pp. 995–1009, 2023. https://doi.org/10.1122/8.0000659

S. T. Chan, S. Varchanis, S. J. Haward, and A. Q. Shen, “Edge fracture of thixotropic elastoviscoplastic liquid bridges,” PNAS Nexus, vol. 2, Art. no. pgad042, 2023. https://doi.org/10.1093/pnasnexus/pgad042

A. Syrakos, O. Oxtoby, E. De Villiers, S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “A unification of least-squares and Green-Gauss gradients under a common projection-based gradient reconstruction framework,” Mathematics and Computers in Simulation, vol. 205, pp. 108–141, 2023. https://doi.org/10.1016/j.matcom.2022.09.008

S. Varchanis, J. Tsamopoulos, A. Q. Shen, and S. J. Haward, “Reduced and increased flow resistance in shear-dominated flows of Oldroyd-B fluids,” Journal of Non-Newtonian Fluid Mechanics, vol. 300, Art. no. 104698, 2022. https://doi.org/10.1016/j.jnnfm.2021.104698

V. Mitsoulas, S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “Dynamics and apparent permeability of the glycocalyx layer: Start-up and pulsating shear experiments in silico,” Physical Review Fluids, vol. 7, Art. no. 013102, 2022. https://doi.org/10.1103/PhysRevFluids.7.013102

S. T. Chan, S. Varchanis, S. J. Haward, and A. Q. Shen, “Torsional instability of constant viscosity elastic liquid bridges,” Soft Matter, vol. 18, pp. 1965–1977, 2022. https://doi.org/10.1039/D1SM01804C

V. Calabrese, S. Varchanis, S. J. Haward, and A. Q. Shen, “Alignment of colloidal rods in crowded environments,” Macromolecules, vol. 55, pp. 5610–5620, 2022. https://doi.org/10.1021/acs.macromol.2c00769

S. Varchanis, S. J. Haward, C. C. Hopkins, J. Tsamopoulos, and A. Q. Shen, “Evaluation of constitutive models for shear-banding wormlike micellar solutions in simple and complex flows,” Journal of Non-Newtonian Fluid Mechanics, vol. 307, Art. no. 104855, 2022. https://doi.org/10.1016/j.jnnfm.2022.104855

P. Moschopoulos, S. Varchanis, A. Syrakos, Y. Dimakopoulos, and J. Tsamopoulos, “S-PAL: A stabilized finite element formulation for computing viscoplastic flows,” Journal of Non-Newtonian Fluid Mechanics, vol. 309, Art. no. 104883, 2022. https://doi.org/10.1016/j.jnnfm.2022.104883

S. Varchanis and J. Tsamopoulos, “Numerical simulations of interfacial and elastic instabilities,” Science Talks, vol. 3, Art. no. 100053, 2022. https://doi.org/10.1016/j.sctalk.2022.100053

S. Varchanis, A. Kordalis, Y. Dimakopoulos, and J. Tsamopoulos, “Adhesion, cavitation, and fibrillation during the debonding process of pressure sensitive adhesives,” Physical Review Fluids, vol. 6, Art. no. 013301, 2021. https://doi.org/10.1103/PhysRevFluids.6.013301

V. Calabrese, S. Varchanis, S. J. Haward, J. Tsamopoulos, and A. Q. Shen, “Structure-property relationship of a soft colloidal glass in simple and mixed flows,” Journal of Colloid and Interface Science, vol. 601, pp. 454–466, 2021. https://doi.org/10.1016/j.jcis.2021.05.103

A. Kordalis, S. Varchanis, G. Ioannou, Y. Dimakopoulos, and J. Tsamopoulos, “Investigation of the extensional properties of elasto-visco-plastic materials in cross-slot geometries,” Journal of Non-Newtonian Fluid Mechanics, vol. 296, Art. no. 104627, 2021. https://doi.org/10.1016/j.jnnfm.2021.104627

S. Varchanis, D. Pettas, Y. Dimakopoulos, and J. Tsamopoulos, “Origin of the sharkskin instability: Nonlinear dynamics,” Physical Review Letters, vol. 127, Art. no. 088001, 2021. https://doi.org/10.1103/PhysRevLett.127.088001

P. Moschopoulos, A. Spyridakis, S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “The concept of elasto-visco-plasticity and its application to a bubble rising in yield stress fluids,” Journal of Non-Newtonian Fluid Mechanics, vol. 297, Art. no. 104670, 2021. https://doi.org/10.1016/j.jnnfm.2021.104670

S. J. Haward, C. C. Hopkins, S. Varchanis, and A. Q. Shen, “Bifurcations in flows of complex fluids around microfluidic cylinders,” Lab on a Chip, vol. 21, pp. 4041–4059, 2021. https://doi.org/10.1039/D1LC00128K

S. Varchanis, S. J. Haward, C. C. Hopkins, A. Syrakos, A. Q. Shen, Y. Dimakopoulos, and J. Tsamopoulos, “Transition between solid and liquid state of yield-stress fluids under purely extensional deformations,” Proceedings of the National Academy of Sciences, vol. 117, pp. 12611–12617, 2020. https://doi.org/10.1073/pnas.1922242117

S. Varchanis, A. Syrakos, Y. Dimakopoulos, and J. Tsamopoulos, “PEGAFEM-V: A new Petrov-Galerkin finite element method for free surface viscoelastic flows,” Journal of Non-Newtonian Fluid Mechanics, vol. 284, Art. no. 104365, 2020. https://doi.org/10.1016/j.jnnfm.2020.104365

K. Giannokostas, P. Moschopoulos, S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “Advanced constitutive modeling of the thixotropic elasto-visco-plastic behavior of blood: Description of the model and rheological predictions,” Materials, vol. 13, Art. no. 4184, 2020. https://doi.org/10.3390/ma13184184

S. Varchanis, C. C. Hopkins, A. Q. Shen, J. Tsamopoulos, and S. J. Haward, “Asymmetric flows of complex fluids past confined cylinders: A comprehensive numerical study with experimental validation,” Physics of Fluids, vol. 32, Art. no. 053103, 2020. https://doi.org/10.1063/5.0008783

S. Varchanis, A. Syrakos, Y. Dimakopoulos, and J. Tsamopoulos, “A new finite element formulation for viscoelastic flows: Circumventing simultaneously the LBB condition and the high-Weissenberg number problem,” Journal of Non-Newtonian Fluid Mechanics, vol. 267, pp. 78–97, 2019. https://doi.org/10.1016/j.jnnfm.2019.04.003

S. Varchanis, G. Makrigiorgos, P. Moschopoulos, Y. Dimakopoulos, and J. Tsamopoulos, “Modeling the rheology of thixotropic elasto-visco-plastic materials,” Journal of Rheology, vol. 63, pp. 609–639, 2019. https://doi.org/10.1122/1.5049136

S. Varchanis, Y. Dimakopoulos, C. Wagner, and J. Tsamopoulos, “How viscoelastic is human blood plasma?,” Soft Matter, vol. 14, pp. 4238–4251, 2018. https://doi.org/10.1039/C8SM00061A

S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “Evaluation of tube models for linear entangled polymers in simple and complex flows,” Journal of Rheology, vol. 62, pp. 25–47, 2018. https://doi.org/10.1122/1.5009197

A. Syrakos, S. Varchanis, Y. Dimakopoulos, A. Goulas, and J. Tsamopoulos, “A critical analysis of some popular methods for the discretisation of the gradient operator in finite volume methods,” Physics of Fluids, vol. 29, Art. no. 127103, 2017. https://doi.org/10.1063/1.4997682

S. Varchanis, Y. Dimakopoulos, and J. Tsamopoulos, “Steady film flow over a substrate with rectangular trenches forming air inclusions,” Physical Review Fluids, vol. 2, Art. no. 124001, 2017. https://doi.org/10.1103/PhysRevFluids.2.124001