scholarly journals Relationship between solar energetic oxygen flux and MHD shock mach number

2012 ◽  
Author(s):  
K. Liou ◽  
C. -C. Wu ◽  
M. Dryer ◽  
S. T. Wu ◽  
D. B. Berdichevsky ◽  
...  
Keyword(s):  
Mach Number ◽  
Oxygen Flux ◽  
Shock Mach Number

scholarly journals The isothermal evolution of a shock-filament interaction

2019 ◽  
Vol 491 (4) ◽  
pp. 4783-4801 ◽  
Author(s):  
K J A Goldsmith ◽  
J M Pittard
Keyword(s):  
Mach Number ◽  
Density Contrast ◽  
Mixing Times ◽  
Filament Length ◽  
Large Role ◽  
Hydrodynamic Simulations ◽  
The Core ◽  
Adiabatic Shock ◽  
Shock Mach Number ◽  
Isothermal Regime

ABSTRACT Studies of filamentary structures that are prevalent throughout the interstellar medium are of great significance to a number of astrophysical fields. Here, we present 3D hydrodynamic simulations of shock-filament interactions where the equation of state has been softened to become almost isothermal. We investigate the effect of such an isothermal regime on the interaction (where both the shock and filament are isothermal), and we examine how the nature of the interaction changes when the orientation of the filament, the shock Mach number, and the filament density contrast are varied. We find that only sideways-oriented filaments with a density contrast of 102 form a three-rolled structure, dissimilar to the results of a previous study. Moreover, the angle of orientation of the filament plays a large role in the evolution of the filament morphology: the greater the angle of orientation, the longer and less turbulent the wake. Turbulent stripping of filament material leading to fragmentation of the core occurs in most filaments; however, filaments orientated at an angle of 85° to the shock front do not fragment and are longer lived. In addition, values of the drag time are influenced by the filament length, with longer filaments being accelerated faster than shorter ones. Furthermore, filaments in an isothermal regime exhibit faster acceleration than those struck by an adiabatic shock. Finally, we find that the drag and mixing times of the filament increase as the angle of orientation of the filament is increased.

Equilibrium Thermodynamic Properties Behind Strong Shocks in Helium

1968 ◽  
Vol 72 (686) ◽  
pp. 155-159
Author(s):  
M. Lalor ◽  
H. Daneshyar
Keyword(s):  
Mach Number ◽  
Partition Function ◽  
Shock Waves ◽  
Thermodynamic Properties ◽  
Strong Shock ◽  
Equilibrium Thermodynamic ◽  
Ionized Gas ◽  
Number Range ◽  
Shock Mach Number ◽  
Strong Shock Waves

Summary Tables of equilibrium thermodynamic properties of the ionized gas formed behind strong shock waves in Helium are presented, in the Mach number range 10 to 30, for initial pressures of 0-1, 0-5, 1, 5, 10, 50, 100 torr. The effect of the inclusion of the full partition function series is demonstrated in the Mach number range 20 to 30. A numerical solution has been developed such that the only experimental quantities required for its use are the shock Mach number and the pre-shock conditions.

Linear relationship between Hugoniot temperature and shock Mach number

Shock Waves ◽  
1998 ◽  
Vol 8 (6) ◽  
pp. 321-325
Author(s):  
C. Renero ◽  
F.E. Prieto
Keyword(s):  
Mach Number ◽  
Linear Relationship ◽  
Shock Mach Number

scholarly journals Exploring the role of cosmological shock waves in the Dianoga simulations of galaxy clusters

2021 ◽  
Author(s):  
S Planelles ◽  
S Borgani ◽  
V Quilis ◽  
G Murante ◽  
V Biffi ◽  
...  
Keyword(s):  
Mach Number ◽  
Shock Waves ◽  
Galaxy Clusters ◽  
Cluster Mass ◽  
Mach Number Distribution ◽  
Disturbed Systems ◽  
Shock Mach Number ◽  
Formation And Evolution ◽  
Massive Clusters

Abstract Cosmological shock waves are ubiquitous to cosmic structure formation and evolution. As a consequence, they play a major role in the energy distribution and thermalization of the intergalactic medium (IGM). We analyse the Mach number distribution in the Dianoga simulations of galaxy clusters performed with the SPH code GADGET-3. The simulations include the effects of radiative cooling, star formation, metal enrichment, supernova and active galactic nuclei feedback. A grid-based shock-finding algorithm is applied in post-processing to the outputs of the simulations. This procedure allows us to explore in detail the distribution of shocked cells and their strengths as a function of cluster mass, redshift and baryonic physics. We also pay special attention to the connection between shock waves and the cool-core/non-cool core (CC/NCC) state and the global dynamical status of the simulated clusters. In terms of general shock statistics, we obtain a broad agreement with previous works, with weak (low-Mach number) shocks filling most of the volume and processing most of the total thermal energy flux. As a function of cluster mass, we find that massive clusters seem more efficient in thermalising the IGM and tend to show larger external accretion shocks than less massive systems. We do not find any relevant difference between CC and NCC clusters. However, we find a mild dependence of the radial distribution of the shock Mach number on the cluster dynamical state, with disturbed systems showing stronger shocks than regular ones throughout the cluster volume.

Experimental investigation of diaphragm material combinations in a small-scale shock tube

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anugya Singh ◽  
Aravind Satheesh Kumar ◽  
Kannan B.T.
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Shock Tube ◽  
Production Capacity ◽  
Incident Shock ◽  
Small Scale ◽  
Content Type ◽  
Shock Mach Number ◽  
Reinforcing Material ◽  
Shock Wave Mach Number

Purpose The purpose of this study is to experimentally investigate the trends in shock wave Mach number that were observed when different diaphragm material combinations were used in the small-scale shock tube. Design/methodology/approach A small-scale shock tube was designed and fabricated having a maximum Mach number production capacity to be 1.5 (theoretically). Two microphones attached in the driven section were used to calculate the shock wave Mach number. Preliminary tests were conducted on several materials to obtain the respective bursting pressures to decide the final set of materials along with the layered combinations. Findings According to the results obtained, 95 GSM tracing paper was seen to be the strongest reinforcing material, followed by 75 GSM royal executive bond paper and regular 70 GSM paper for aluminium foil diaphragms. The quadrupled layered diaphragms revealed a variation in shock Mach number based on the position of the reinforcing material. In quintuple layered combinations, the accuracy of obtaining a specific Mach number was seen to be increasing. Optimization of the combinations based on the production of the shock wave Mach number was carried out. Research limitations/implications The shock tube was designed taking maximum incident shock Mach number as 1.5, the experiments conducted were found to achieve a maximum Mach number of 1.437. Thus, an extension to further experiments was avoided considering the factor of safety. Originality/value The paper presents a detailed study on the effect of change in the material and its position in the layered diaphragm combinations, which could lead to variation in Mach numbers that are produced. This could be used to obtain a specific Mach number for a required study accurately, with a low-cost setup.

An investigation of the metastable argon atoms in a shock tube driven atomic beam

1969 ◽  
Vol 312 (1508) ◽  
pp. 1-12
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Atomic Beam ◽  
Rotating Disk ◽  
Copper Surface ◽  
Reflected Shock Wave ◽  
Reflected Shock ◽  
Wave Measurements ◽  
Shock Mach Number ◽  
Primary Shock

Metastable atoms and photons have been detected in the beam by their ability to eject electrons from a copper surface. The contribution due to the metastable atoms was found by 'chopping’ the beam with a rotating disk so that the signals due to metastable atoms were displaced in time relative those due to photoemission. The velocity of the atoms found agreed well with the theoretical flow velocity of gas expanding supersonically from the region behind the reflected shock wave. Measurements have been made for primary shock Mach numbers between 6.1 and 8.7 and typical values of the intensity and velocity of the atoms for a primary shock Mach number of 6.34 are 1 x 10 16 metastable atoms sr -1 s -1 and 3.08 x 10 3 m/s respectively.

Boundary Layer Suction via a Slot in a Transonic Compressor: Numerical Parameter Study and First Experiments

2004 ◽  
Author(s):  
K. Hubrich ◽  
A. Bo¨lcs ◽  
P. Ott
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Mach Number ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Parameter Study ◽  
Flow Angle ◽  
Boundary Layer Suction ◽  
Transonic Compressor ◽  
Shock Mach Number

In the present paper a numerical and experimental study aiming at the enhancement of the working range of a transonic compressor via boundary layer suction (BLS) is presented. The main objective of the investigation is to study the influence of BLS on the interference between shock wave and boundary layer and to identify the possible benefit of BLS on the compressor working characteristics. An extensive numerical study has been carried out for the DATUM blade and for 2 different suction location configurations for one speed line and varying back-pressure levels, ranging from choked conditions to stall. It was found that the working range of the transonic compressor with a nominal inlet Mach number of 1.2 and a nominal pre-shock Mach number of 1.35 could be increased by sucking 2% of flow on the SS away, in such a way that the maximum pressure ratio and maximum diffusion could both be increased by 10%, when compared to the DATUM case. For smaller pressure ratios with respect to the design pressure ratio, the BLS is located in a supersonic flow region and thus creates additional losses due to a more divergent flow channel, which additionally accelerates the flow and results in a higher pre-shock Mach number creating higher losses. First measurements carried out in LTTs annular cascade, do show reasonable agreement with the computations in terms of inlet Mach number, flow angle, main shock location and stall limit. The most pronounced difference between measurements and computations is the occurrence of a terminal normal channel shock behind a bowed detached shock wave and a separation on the SS of the blade, which were both not predicted by the CFD.

Some Effects on Conical Diffuser Performance of Preceding Normal Shock Boundary-Layer Interaction

1974 ◽  
Vol 188 (1) ◽  
pp. 607-613 ◽  
Author(s):  
J. L. Livesey ◽  
A. O. Odukwe
Keyword(s):  
Mach Number ◽  
Static Pressure ◽  
Pressure Rise ◽  
Sharp Transition ◽  
Pressure Loss Coefficient ◽  
Boundary Layer Interaction ◽  
Shock Mach Number ◽  
Inlet Conditions ◽  
Comparison Of The Results ◽  
Total Pressure Loss Coefficient

Experimental results are presented for the variation of the static pressure rise coefficient Cp, the transformation efficiency η the total pressure loss coefficient CL and the outlet kinetic energy coefficient ɛ2 with the Mach number and the effective throat length for subsonic conical diffusers with total expansion angles of 5°, 12° and 20° and an overall area ratio of 10:1. The junction between the parallel entry pipe and the diffuser cone is sharp and the diffuser inlet conditions are evaluated from measurements on a plane 1°5 diameters upstream of the diffuser's sharp transition. The shock Mach number was varied from 1°05 to 1°25 whilst the diffuser inlet Reynolds number varied between 9°0 × 105 and 1°22 × 106. A comparison of the results with those of diffusers preceded by wholly subsonic flow in the entry pipe shows the beneficial effect of interaction, the most significant gains being with the lowest angle diffuser.

The Effect of Particles on Blast Waves in a Dusty Gas

1980 ◽  
Vol 35 (12) ◽  
pp. 1330-1336 ◽  
Author(s):  
Fumio Higashino ◽  
Tateyuki Suzuki
Keyword(s):  
Mach Number ◽  
Volume Fraction ◽  
Expansion Method ◽  
Blast Waves ◽  
Dusty Gas ◽  
First Order ◽  
Shock Mach Number ◽  
The Difference ◽  
Temperature Equilibrium ◽  
Series Expansion Method

Abstract The effect of suspended particles on cylindrical blast waves is investigated by making use of a series expansion method with respect to 1/M2 take off [2], where M is the shock Mach number. Velocity and temperature equilibrium between the gas and the particles is assumed. As a result, one finds that the particles are assembled near the shock front and that behind it the slopes of the pressure and velocity profiles increase, as the volume fraction of particles increases. The difference between the zeroth and first order solutions becomes the smaller, the larger the volume fraction of the particles. The decay rate of a blast wave in a dusty gas is greater than in a dust-free gas.

Sign in / Sign up

Export Citation Format

Share Document