Abstract
We consider the dynamics of a rod on the plane in a flow of non-interacting point particles moving at a fixed speed. When colliding with the rod, the particles are reflected elastically and then leave the plane of motion of the rod and do not interact with it. A thin unbending weightless “knitting needle” is fastened to the massive rod. The needle is attached to an anchor point and can rotate freely about it. The particles do not interact with the needle.
The equations of dynamics are obtained, which are piecewise analytic: the phase space is divided into four regions where the analytic formulas are different. There are two fixed points of the system, corresponding to the position of the rod parallel to the flow velocity, with the anchor point at the front and the back. It is found that the former point is topologically a stable focus, and the latter is topologically a saddle. A qualitative description of the phase portrait of the system is obtained.
REFERENCES
Arnold, V. I., Ordinary Differential Equations, Berlin: Springer, 2006.
Newton, I., The Mathematical Principles of Natural Philosophy, Berkeley, Calif.: Univ. of California, 1999.
Buttazzo, G., Ferone, V., and Kawohl, B., Minimum Problems over Sets of Concave Functions and Related Questions, Math. Nachr., 1995, vol. 173, pp. 71–89.
Brock, F., Ferone, V., and Kawohl, B., A Symmetry Problem in the Calculus of Variations, Calc. Var. Partial Differential Equations, 1996, vol. 4, no. 6, pp. 593–599.
Lachand-Robert, Th. and Oudet, É., Minimizing within Convex Bodies Using a Convex Hull Method, SIAM J. Optim., 2005, vol. 16, no. 2, pp. 368–379.
Wachsmuth, G., The Numerical Solution of Newton’s Problem of Least Resistance, Math. Program. Ser. A, 2014, vol. 147, no. 1–2, pp. 331–350.
Plakhov, A., A Solution to Newton’s Least Resistance Problem Is Uniquely Defined by Its Singular Set, Calc. Var. Partial Differential Equations, 2022, vol. 61, no. 5, Paper No. 189, 37 pp.
Plakhov, A. and Tchemisova, T., Problems of Optimal Transportation on the Circle and Their Mechanical Applications, J. Differential Equations, 2017, vol. 262, no. 3, pp. 2449–2492.
Plakhov, A., Billiards and Two-Dimensional Problems of Optimal Resistance, Arch. Ration. Mech. Anal., 2009, vol. 194, no. 2, pp. 349–381.
Angel, O., Burdzy, K., and Sheffield, S., Deterministic Approximations of Random Reflectors, Trans. Amer. Math. Soc., 2013, vol. 365, no. 12, pp. 6367–6383.
Plakhov, A., Tchemisova, T., and Gouveia, P., Spinning Rough Disc Moving in a Rarefied Medium, Proc. R. Soc. Lond. Ser. A Math. Phys. Eng. Sci., 2010, vol. 466, no. 2119, pp. 2033–2055.
Kryzhevich, S., Motion of a Rough Disc in Newtonian Aerodynamics, in EmC-ONS 2014: Optimization in the Natural Sciences, A. Plakhov, T. Tchemisova, A. Freitas (Eds.), Commun. Comput. Inf. Sci., vol. 499, Cham: Springer, 2015, pp. 3–19.
Rudzis, P., Rough Collisions, arXiv:2203.09102 (2022).
Kryzhevich, S. and Plakhov, A., Billiard in a Rotating Half-Plane, J. Dyn. Control Syst., 2023, vol. 29, no. 4, pp. 1695–1707.
Kryzhevich, S. and Plakhov, A., Rotating Rod and Ball, J. Math. Anal. Appl., 2024, in press.
Lokshin, B. Ya. and Samsonov, V. A., On a Heuristic Model of an Aerodynamical Pendulum, Fundam. Prikl. Mat., 1998, vol. 4, no. 3, pp. 1047–1061 (Russian).
Shakhov, E. M., The Oscillations of a Satellite Probe Towed on an Inextensible Line in an Inhomogeneous Atmosphere, J. Appl. Math. Mech., 1988, vol. 52, no. 4, pp. 440–444; see also: Prikl. Mat. Mekh., 1988, vol. 52, no. 4, pp. 567-572.
Zhuk, V. I. and Shakhov, E. M., Oscillations of a Tethered Satellite of Small Mass under the Effect of Aerodynamic and Gravitational Forces, Kosmicheskie Issledovaniya, 1990, vol. 28, no. 6, pp. 820–830 (Russian).
Lokshin, B. Ya., Samsonov, V. A., and Shamolin, M. V., Pendulum Systems with Dynamical Symmetry, J. Math. Sci. (N.Y.), 2017, vol. 227, no. 4, pp. 461–519.
Rybnikova, T. A. and Treshchev, D. V., Existence of Invariant Tori in the Problem of the Motion of a Satellite with a Solar Sail, Kosmicheskie Issledovaniya, 1990, vol. 28, no. 2, pp. 309–312 (Russian).
Funding
The work of AD was supported by the MSU Program of Development, Project No 23-SCH5-25. The work of AP was supported by the Center for R & D in Mathematics and Applications, refs. UIDB/04106/2020 and UIDP/04106/2020, and by CoSysM3, ref. 2022.03091.PTDC, through FCT.
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
The authors declare that they have no conflicts of interest.
Additional information
PUBLISHER’S NOTE
Pleiades Publishing remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
MSC2010
34A34, 34C60, 70E17, 70G60
Rights and permissions
About this article
Cite this article
Davydov, A., Plakhov, A. Dynamics of a Pendulum in a Rarefied Flow. Regul. Chaot. Dyn. 29, 134–142 (2024). https://doi.org/10.1134/S1560354724010088
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1560354724010088