Abstract
The dynamics of a continuous medium in a pipe is not exhausted by spontaneous unsteady turbulence vortices (first seen in flashes of light and generated at high Reynolds numbers), which permanently level the parabolic velocity profile in the pipe. The ambient space also includes steady swirls and curls, which are usually approximated by analytical dependences decomposable in power series. It turns out that, in the Kochin–Yudovich boundary value flow problem, the existence of an ideal incompressible steady flow that is arbitrarily smooth, but not analytic (and, hence, a phantom, i.e., it cannot be classically approximated by polynomials with any prescribed degree of accuracy or, in other words, cannot be computed exactly, but is established over time) is also reduced to vortices of this type. Specifically, the existence analysis is reduced to finding an infinitely smooth uncomputable mass rate of such vortices in the form of a stream function solving the two-dimensional Dirichlet problem for the negative Laplacian with a right-hand side specified as an infinitely smooth Sobolev cutoff function, which was introduced as early as the 1930s and later became known as a Friedrichs mollifier. This problem is briefly discussed below.
Similar content being viewed by others
REFERENCES
S. L. Sobolev, “A new method for solving the Cauchy problem for partial differential equations of normal hyperbolic type,” Mat. Sb. 1 (1), 39–72 (1936).
K. O. Friedrichs, “The identity of weak and strong extensions of differential operators,” Trans. Am. Math. Soc. 55, 132–151 (1944).
A. A. Dezin, “A class of vector fields,” in Complex Analysis and Its Applications (Nauka, Moscow, 1978), pp. 203–208 [in Russian].
A. A. Dezin, Partial Differential Equations: An Introduction to a General Theory of Linear Boundary Value Problems (Nauka, Moscow, 1980; Springer, Berlin, 1987).
E. M. Landis, Second-Order Equations of Elliptic and Parabolic Type (Nauka, Moscow, 1971; Am. Math. Soc., Providence, R.I., 1997).
I. Ekeland and R. Temam, Convex Analysis and Variational Problems (North-Holland, Amsterdam, 1976).
S. L. Sobolev, Some Applications of Functional Analysis in Mathematical Physics (Am. Math. Soc., Providence, R.I., 1963; Nauka, Moscow, 1988).
S. Agmon, A. Douglis, and L. Nirenberg, “Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions I, II” Commun. Pure Appl. Math. 12 (4), 623–727 (1959);
Commun. Pure Appl. Math. 17 (1), 35–92 (1964).
V. I. Yudovich, “A two-dimensional problem of unsteady flow of an ideal incompressible fluid across a given domain,” Am. Math. Soc. Transl. 57, 277–304 (1966).
O. V. Troshkin, “Topological analysis of the structure of hydrodynamic flows,” Russ. Math. Surv. 43 (4), 153–190 (1988).
O. V. Troshkin, “A two-dimensional flow problem for steady-state Euler equations,” Math. USSR-Sb. 66 (2), 363–382 (1990).
O. A. Ladyzhenskaya, The Mathematical Theory of Viscous Incompressible Flow, Reprint of 1963 Edition (Martino Fine Books, Eastford, 2014).
H. K. Moffatt, “Generalized vortex rings with and without swirl,” Fluid Dyn. Res. 3, 22–30 (1988).
O. V. Troshkin, “On smooth vortex catastrophe of uniqueness for stationary flows of an ideal fluid,” Comput. Math. Math. Phys. 59 (10), 1742–1752 (2019).
Funding
This work was performed within the state assignment of the Federal Research Center Scientific Research Institute for System Analysis of the Russian Academy of Sciences (fundamental scientific research, GP 14) on subject no. 0065-2019-0005 “Mathematical modeling of dynamic processes in deformable and reacting media on multiprocessor computer systems,” no. AAAA-A19-119011590092-6.
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated by I. Ruzanova
Rights and permissions
About this article
Cite this article
Troshkin, O.V. Vortex Phantoms in the Stationary Kochin–Yudovich Flow Problem. Comput. Math. and Math. Phys. 61, 664–667 (2021). https://doi.org/10.1134/S0965542521040114
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0965542521040114