Gas Flows in Ventilated Supercavities

Three-dimensional ventilated supercavity on a maneuvering trajectory

“…The gas leakage of a supercavity at high speed is dominated by toroidal vortices; nevertheless, the gas-leakage mechanism needs to be further explored in connection with ventilation delay and the vehicle's afterbody piercing the cavity surface (Wosnik and Arndt, 2009). For now, Spurk's gas-entrainment model (Spurk, 2002) agrees relatively well with experiments (Savchenko and Savchenko, 2012) and numerical simulations (Kinzel et al, 2009) as follows:…”

Rediscovery of Rhabdomastix (Rhabdomastix) incapax Starý, 2005 (Diptera, Limoniidae), a crane fly species flightless in both sexes and probably endemic to Sardinia

“…On the other hand, in Dicranomyia (Dicranomyia) reductissima (Alexander, 1952) [= lindrothi (Tjeder, 1963)] (Limoniidae), described from Tibet (as lindrothi from Alaska), a species micropterous in the male (female unknown), the legs are very slender and the antennae normally developed (Tjeder 1963). [Note: A form characterized as stenopterous in both sexes, interpreted as belonging to this species, was recorded from Mongolia and Tuva Region in Russia (Savchenko 1972). ] Another example of long-legged brachypterous species may be Symplecta (Symplecta) holdgatei (Freeman, 1962) from the Gough Island in the Atlantic Ocean (Jones et al 2003).…”

Re-entrant Gas Flows of High-speed Ventilated Supercavity

“…Since ventilated supercavitation was discovered, researchers have made endeavours in this area and some achievements in the formation, hydrodynamics and stability of supercavity [1][2][3][4][5] , but inner flow structures remain little focused. Unlike natural case, where vapor-water mixture interacts [6] , there are gas vortex ring structures inside ventilated supercavity [7,8] . It is inextricably linked with gas loss [9,10] , which not only determines supercavity tail closure [11] , but also is crucial to the flow stability and control [12,13] .…”