Plane turbulent mixing between two streams of different gases (especially nitrogen and helium) was studied in a novel apparatus. Spark shadow pictures showed that, for all ratios of densities in the two streams, the mixing layer is dominated by large coherent structures. High-speed movies showed that these convect at nearly constant speed, and increase their size and spacing discontinuously by ...

When stimulated Raman pumping (SRP) is applied to a stream of isolated molecules, such as found in a supersonic molecular beam expansion, we show that SRP can neither saturate nor power broaden a molecular transition connecting two metastable levels that is resonant with the energy difference between the pump and Stokes laser pulses. Using the optical Bloch-Feynman equations, we discuss the pum...

JetPeel (Tav-Tech Ltd., Yehud, Israel) is a new device for cosmetic resurfacing of the facial skin. It uses a new technology of a 2-phase stream that creates a jet composed of gas (oxygen) and microdroplets of fluid (saline) accelerated to supersonic velocities. This jet impacts the skin, causing gentle and accurate cosmetic peeling. Our preclinical and clinical experience with the JetPeel for ...

Large-eddy simulations are performed to analyze film cooling in supersonic combustion ramjets (Scramjets). The transonic film cooling flow is injected through a slot parallel to a Ma = 2.44 main stream with a fully turbulent boundary layer. The injection Mach number is Mai = 1.2 and adiabatic wall conditions are imposed. The cooling effectiveness is investigated for adverse and favorable pressu...

We are concerned with global steady subsonic flows through general infinitely long nozzles for the full Euler equations. The problem is formulated as a boundary value problem in the unbounded domain for a nonlinear elliptic equation of second order in terms of the stream function. It is established that, when the oscillation of the entropy and Bernoulli functions at the upstream is sufficiently...

The problem of the efficiency of particle acceleration for parabolic poloidal magnetic field is considered within the approach of steady axisymmetric MHD flow. For the large Michel magnetization parameter σ it is possible to linearize the stream equation near the force-free solution and to solve the problem self-consistently as was done by Beskin, Kuznetsova & Rafikov (1998) for monopole magnet...

An algorithm for computing transonic flow fields about fighter-type aircraft is described in the paper. The compressible Euler equations are solved numerically using a vertex-based, finite volume multigrid scheme. The space around the aircraft is discretized with a single-block H-0 mesh which is generated by the union of separate Omeshes around successive cross sections of the aircraft. The dis...

The variability of sea surface temperatures (SSTs) at multidecadal and longer timescales is poorly constrained, primarily because instrumental records are short and proxy records are noisy. Through applying a new noise filtering technique to a global network of late Holocene SST proxies, we estimate SST variability between annual and millennial timescales. Filtered estimates of SST variability ...

Heliospheric (HSP) radio emission detected by the Voyager spacecraft between 1.8 kHz and 3.6 kHz from the distant heliosphere is interpreted as emission generated close to and at the heliopause (HP), the interface between the ionised very local interstellar (LIC) gas and the supersonic solar wind (SW) stream. Radio emission is assumed to be triggered by secondary charge exchange ionisation of i...

We consider closed-loop control of a two-dimensional supersonic boundary layer at $M=4.5$ that aims reducing the linear growth second Mack mode instabilities. These instabilities are first characterized with local spatial and global resolvent analyses, which allow us to refine strategy select appropriate actuators sensors. After input–output reduced-order models have been identified, multi-crit...