相关论文: Impact
When a granular material is impacted by a sphere, its surface deforms like a liquid yet it preserves a circular crater like a solid. Although the mechanism of granular impact cratering by solid spheres is well explored, our knowledge on…
In this fluid dynamics video, we present an experimental investigation of the shape of impact craters in granular materials. Complex crater shapes, including polygons, have been observed in many terrestrial planets as well as moons and…
Granular material that is bound by the low gravity of a small asteroid is mobilized by slow velocity impacts. These splashes generated by impacts might play an important role in sculpting the asteroid's surface. In laboratory experiments we…
The collapse of an inclined cohesive granular layer triggered by a certain perturbation can be a model for not only landslides on Earth but also relaxations of asteroidal surface terrains. To understand such terrain dynamics, we conduct a…
Impacts play a fundamental role in shaping the physical and chemical properties of the objects in our Solar System. Given the challenges in replicating such collisions through laboratory experiments, computer simulations are an important…
As a droplet impacts on a granular substrate, both the intruder and the target deform, during which the liquid may penetrate into the substrate. {These three aspects together distinguish} it from other impact phenomena in the literature. We…
Impact cratering plays a crucial role in shaping the surfaces of small bodies, satellites, and planets, providing insights into their formation and the history of the Solar System. Small bodies are often covered with low-cohesion regolith.…
This contribution is a first step aiming to address a general question: what can be concluded on impact craters which exist on various planetary system objects, by combining astronomical data and known theoretical results from solid state…
The surfaces of solid objects in our planetary system are dappled with craters. Some of them are due to impacts of various solid projectiles into the surfaces of the objects. A smaller part of these craters is of volcanic origin. %Some of…
In laboratory experiments, high speed videos are used to detect and track mm-size surface particle motions caused by a low velocity normal impact into sand. Outside the final crater radius and prior to the landing of the ejecta curtain,…
The penetration by a gravity driven impact of a solid sphere into a granular medium is studied by two-dimensional simulations. The scaling laws observed experimentally for both the final penetration depth and the stopping time with the…
Pressure is a key parameter in the physics and chemistry of planet formation and evolution. Previous studies have erroneously assumed that internal pressures monotonically increase with the mass of a body. Using smoothed particle…
Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most…
Planets are expected to conclude their growth through a series of giant impacts: energetic, global events that significantly alter planetary composition and evolution. Computer models and theory have elucidated the diverse outcomes of giant…
We develop an original apparatus of the granular impact experiment by which the incident angle of the solid projectile and inclination angle of the target granular layer can be systematically varied. Whereas most of the natural cratering…
Compound drop impacting on a solid surface is of considerable importance in industrial applications, such as combustion, food industry, and drug encapsulation. An intriguing phenomenon associated with this process is the occurrence of…
We consider how an impact generated seismic pulse affects the surface of an asteroid distant from the impact site. With laboratory experiments on dry polydisperse gravel mixtures, we track the trajectories of particles ejected from the…
Friction plays a fundamental role in many natural processes, including earthquakes, landslides, and volcanic eruptions. Earthquakes occur when highly compressed fault surfaces accumulate large enough shear stresses, causing the faults to…
Giant impacts, the collisions between planetary embryos, play a crucial role in sculpting the planets and their orbital architectures. Numerical simulations have advanced our understanding of these events, enabling estimations of mass and…
The early stages of drop impact onto a solid surface are considered. Detailed numerical simulations and detailed asymptotic analysis of the process reveal a self-similar structure both for the velocity field and the pressure field. The…