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In fluid dynamics, slosh refers to the movement of liquid inside another object (which is, typically, also undergoing motion). Strictly speaking, the liquid must have a free surface to constitute a slosh dynamics problem, where the dynamics of the liquid can interact with the container to alter the system dynamics significantly.〔Moiseyev, N.N. & V.V. Rumyantsev. "Dynamic Stability of Bodies Containing Fluid." Springer-Verlag, 1968.〕 Important examples include propellant slosh in spacecraft tanks and rockets (especially upper stages), and the free surface effect (cargo slosh) in ships and trucks transporting liquids (for example oil and gasoline). However, it has become common to refer to liquid motion in a completely filled tank, i.e. without a free surface, as "fuel slosh". Such motion is characterized by "inertial waves" and can be an important effect in spinning spacecraft dynamics. Extensive mathematical and empirical relationships have been derived to describe liquid slosh. These types of analyses are typically undertaken using computational fluid dynamics and finite element methods to solve the fluid-structure interaction problem, especially if the solid container is flexible. Relevant fluid dynamics non-dimensional parameters include the Bond number, the Weber number, and the Reynolds number. Slosh is an important effect for spacecraft,〔Reyhanoglu, M. "Maneuvering control problems for a spacecraft with unactuated fuel slosh dynamics". Control Applications, 2003. Proc 2003 IEEE Conference. Volume 1, 23–25 June 2003, pp695-699.〕 ships,〔 and some aircraft. Slosh was a factor in the Falcon 1 second test flight anomaly, and has been implicated in various other spacecraft anomalies, including a near-disaster〔Veldman, A.E.P. et al. "The Numerical Simulation of Liquid Sloshing On-Board Spacecraft." J. Comp. Phys. 224 (2007) 82-99.〕 with the Near Earth Asteroid Rendezvous (NEAR Shoemaker) satellite. == Spacecraft effects == Liquid slosh in microgravity〔Monti, R. "Physics of Fluids in Microgravity." CRC, 2002.〕〔Antar, B.N. & V.S. Nuotio-Antar. "Fundamentals of Low Gravity Fluid Dynamics and Heat Transfer." CRC, 1994.〕 is relevant to spacecraft, most commonly Earth-orbiting satellites, and must take account of liquid surface tension which can alter the shape (and thus the eigenvalues) of the liquid slug. Typically, a large part of the mass fraction of a satellite is liquid propellant at/near Beginning of Life (BOL), and slosh can adversely affect satellite performance in a number of ways. For example, propellant slosh can introduce uncertainty in spacecraft attitude (pointing) which is often called jitter. Similar phenomena can cause pogo oscillation and can result in structural failure of space vehicle. Another example is problematic interaction with the spacecraft Attitude Control System (ACS), especially for spinning satellites〔Hubert, C. "Behavior of Spinning Space Vehicles with Onboard Liquids." NASA GSFC Symposium, 2003.〕 which can suffer resonance between slosh and nutation, or adverse changes to the rotational inertia. Because of these types of risk, in the 1960s the National Aeronautics and Space Administration (NASA) extensively studied〔Abramson, H.N. "The Dynamic Behavior of Liquids in Moving Containers." NASA SP-106, 1966.〕 liquid slosh in spacecraft tanks, and in the 1990s NASA undertook the ''Middeck 0-Gravity Dynamics Experiment''〔Crawley, E.F. & M.C. Van Schoor & E.B. Bokhour. "The Middeck 0-Gravity Dynamics Experiment: Summary Report", NASA-CR-4500, Mar 1993.〕 on the space shuttle. The European Space Agency has advanced these investigations〔Vreeburg, J.P.B. "Measured States of SLOSHSAT FLEVO", IAC-05-C1.2.09, Oct 2005.〕〔Prins, J.J.M. "SLOSHSAT FLEVO Project, Flight and Lessons Learned", IAC-05-B5.3./B5.5.05, Oct 2005.〕〔Luppes, R. & J.A. Helder & A.E.P. Veldman. "Liquid Sloshing in Microgravity", IAC-05-A2.2.07, Oct 2005.〕〔Vreeburg, J.P.B. "SLOSHSAT Spacecraft Calibration at Stationary Spin Rates." J. Spacecraft & Rockets, v45, n1, p65, Jan/Feb 2008.〕 with the launch of SLOSHSAT. Most spinning spacecraft since 1980 have been tested at the Applied Dynamics Laboratories drop tower using sub-scale models.〔(【引用サイトリンク】url=http://www.fuelslosh.com/SPACECRAFT.html )〕 Extensive contributions have also been made by the Southwest Research Institute, but research is widespread in academia and industry. Research is continuing into slosh effects on in-space propellant depots. In October 2009, the Air Force and United Launch Alliance (ULA) performed an experimental on-orbit demonstration on a modified Centaur upper stage on the DMSP-18 satellite launch in order to improve "understanding of propellant settling and slosh", "The light weight of DMSP-18 allowed of remaining LO2 and LH2 propellant, 28% of Centaur’s capacity", for the on-orbit tests. The post-spacecraft mission extension ran 2.4 hours before the planned deorbit burn was executed.〔 (ulalaunch.com ); Successful Flight Demonstration Conducted by the Air Force and United Launch Alliance Will Enhance Space Transportation: DMSP-18, ''United Launch Alliance'', October 2009, accessed 2011-01-10.〕 NASA's Launch Services Program is working on two on-going slosh fluid dynamics experiments with partners: CRYOTE and SPHERES-Slosh.〔(nasa.gov )〕 ULA has additional small-scale demonstrations of cryogenic fluid management are planned with project CRYOTE in 2012-2014〔 leading to a ULA large-scale cryo-sat propellant depot test under the NASA flagship technology demonstrations program in 2015.〔 (spirit.as.utexas.edu ); ''Propellant Depots Made Simple'', Bernard Kutter, United Launch Alliance, FISO Colloquium, 2010-11-10, accessed 2011-01-10.〕 SPHERES-Slosh with Florida Institute of Technology and Massachusetts Institute of Technology will examine how liquids move around inside containers in microgravity with the SPHERES Testbed on the International Space Station. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Slosh dynamics」の詳細全文を読む スポンサード リンク
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