An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics
We present an approach for the inclusion of nonspherical constituents in high-resolution N -body discrete element method (DEM) simulations. We use aggregates composed of bonded spheres to model nonspherical components. Though the method may be applied more generally, we detail our implementation in...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Planetary Science Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/PSJ/ad0467 |
| _version_ | 1797372599871733760 |
|---|---|
| author | Julian C. Marohnic Joseph V. DeMartini Derek C. Richardson Yun Zhang Kevin J. Walsh |
| author_facet | Julian C. Marohnic Joseph V. DeMartini Derek C. Richardson Yun Zhang Kevin J. Walsh |
| author_sort | Julian C. Marohnic |
| collection | DOAJ |
| description | We present an approach for the inclusion of nonspherical constituents in high-resolution N -body discrete element method (DEM) simulations. We use aggregates composed of bonded spheres to model nonspherical components. Though the method may be applied more generally, we detail our implementation in the existing N -body code pkdgrav . It has long been acknowledged that nonspherical grains confer additional shear strength and resistance to flow when compared with spheres. As a result, we expect that rubble-pile asteroids will also exhibit these properties and may behave differently than comparable rubble piles composed of idealized spheres. Since spherical particles avoid some significant technical challenges, most DEM gravity codes have used only spherical particles or have been confined to relatively low resolutions. We also discuss the work that has gone into improving performance with nonspherical grains, building on pkdgrav 's existing leading-edge computational efficiency among DEM gravity codes. This allows for the addition of nonspherical shapes while maintaining the efficiencies afforded by pkdgrav 's tree implementation and parallelization. As a test, we simulated the gravitational collapse of 25,000 nonspherical bodies in parallel. In this case, the efficiency improvements allowed for an increase in speed by nearly a factor of 3 when compared with the naive implementation. Without these enhancements, large runs with nonspherical components would remain prohibitively expensive. Finally, we present the results of several small-scale tests: spin-up due to the YORP effect, tidal encounters, and the Brazil nut effect. In all cases, we find that the inclusion of nonspherical constituents has a measurable impact on simulation outcomes. |
| first_indexed | 2024-03-08T18:38:11Z |
| format | Article |
| id | doaj.art-9d348d8ed898466ea1121f2a014b2ba8 |
| institution | Directory Open Access Journal |
| issn | 2632-3338 |
| language | English |
| last_indexed | 2024-03-08T18:38:11Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Planetary Science Journal |
| spelling | doaj.art-9d348d8ed898466ea1121f2a014b2ba82023-12-29T10:24:35ZengIOP PublishingThe Planetary Science Journal2632-33382023-01-0141224510.3847/PSJ/ad0467An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile DynamicsJulian C. Marohnic0https://orcid.org/0000-0002-6810-7491Joseph V. DeMartini1https://orcid.org/0000-0003-4396-1728Derek C. Richardson2https://orcid.org/0000-0002-0054-6850Yun Zhang3https://orcid.org/0000-0003-4045-9046Kevin J. Walsh4https://orcid.org/0000-0002-0906-1761Department of Astronomy, University of Maryland, College Park, MD 20742, USA ; jmarohni@umd.eduDepartment of Astronomy, University of Maryland, College Park, MD 20742, USA ; jmarohni@umd.eduDepartment of Astronomy, University of Maryland, College Park, MD 20742, USA ; jmarohni@umd.eduDepartment of Aerospace Engineering, University of Maryland, College Park, MD 20742, USASouthwest Research Institute, Boulder , CO 80302, USAWe present an approach for the inclusion of nonspherical constituents in high-resolution N -body discrete element method (DEM) simulations. We use aggregates composed of bonded spheres to model nonspherical components. Though the method may be applied more generally, we detail our implementation in the existing N -body code pkdgrav . It has long been acknowledged that nonspherical grains confer additional shear strength and resistance to flow when compared with spheres. As a result, we expect that rubble-pile asteroids will also exhibit these properties and may behave differently than comparable rubble piles composed of idealized spheres. Since spherical particles avoid some significant technical challenges, most DEM gravity codes have used only spherical particles or have been confined to relatively low resolutions. We also discuss the work that has gone into improving performance with nonspherical grains, building on pkdgrav 's existing leading-edge computational efficiency among DEM gravity codes. This allows for the addition of nonspherical shapes while maintaining the efficiencies afforded by pkdgrav 's tree implementation and parallelization. As a test, we simulated the gravitational collapse of 25,000 nonspherical bodies in parallel. In this case, the efficiency improvements allowed for an increase in speed by nearly a factor of 3 when compared with the naive implementation. Without these enhancements, large runs with nonspherical components would remain prohibitively expensive. Finally, we present the results of several small-scale tests: spin-up due to the YORP effect, tidal encounters, and the Brazil nut effect. In all cases, we find that the inclusion of nonspherical constituents has a measurable impact on simulation outcomes.https://doi.org/10.3847/PSJ/ad0467Trans-Neptunian objectsAsteroid surfacesNear-Earth objectsAsteroid dynamicsAsteroid rotationAsteroids |
| spellingShingle | Julian C. Marohnic Joseph V. DeMartini Derek C. Richardson Yun Zhang Kevin J. Walsh An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics The Planetary Science Journal Trans-Neptunian objects Asteroid surfaces Near-Earth objects Asteroid dynamics Asteroid rotation Asteroids |
| title | An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics |
| title_full | An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics |
| title_fullStr | An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics |
| title_full_unstemmed | An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics |
| title_short | An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics |
| title_sort | efficient numerical approach to modeling the effects of particle shape on rubble pile dynamics |
| topic | Trans-Neptunian objects Asteroid surfaces Near-Earth objects Asteroid dynamics Asteroid rotation Asteroids |
| url | https://doi.org/10.3847/PSJ/ad0467 |
| work_keys_str_mv | AT juliancmarohnic anefficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT josephvdemartini anefficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT derekcrichardson anefficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT yunzhang anefficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT kevinjwalsh anefficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT juliancmarohnic efficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT josephvdemartini efficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT derekcrichardson efficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT yunzhang efficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics AT kevinjwalsh efficientnumericalapproachtomodelingtheeffectsofparticleshapeonrubblepiledynamics |