scholarly journals Effects of Laser Energy Deposition on the Transition Characteristics of Shock Reflection in the Dual Solution Domain

2019 ◽  
Vol 9 (22) ◽  
pp. 4768
Author(s):  
Seihwan Kim ◽  
Yongchan Kim ◽  
Hyoung Lee
Keyword(s):  
Energy Deposition ◽  
Laser Energy ◽  
Numerical Approach ◽  
Laser Deposition ◽  
Dual Solution ◽  
Shock Reflection ◽  
Deposited Energy ◽  
Solution Region ◽  
Time Required ◽  
Shock Reflections

Numerical simulations were conducted to investigate the transitional characteristics of shock reflections in the dual solution region using laser energy deposition. The numerical approach was validated by comparison to experimental results of the deposition laser energy in front of a blunt model. The simulation results show that the energy deposition in the freestream region can induce a transition of the shock reflection system and the transition characteristics can vary with the position and energy of the laser deposition. As the amount of energy increases, the time required for the transition also increases, and the transition cannot occur when the energy that is applied exceeds a certain level. The time required for the transition can be reduced when the position of energy deposition is moved downstream. The results also show that the transition does not occur regardless of the deposited energy when the laser energy is deposited on the symmetry line.

Numerical Simulation of Radiation Losses in a Decaying Laser Spark Using LBL Method

2015 ◽  
Vol 789-790 ◽  
pp. 287-295
Author(s):  
Ankit Sharma ◽  
Ankit Bansal ◽  
Anil Kishan ◽  
Ratan Joarder
Keyword(s):  
Energy Deposition ◽  
Laser Energy ◽  
Fluid Dynamic ◽  
Dynamic Effects ◽  
Radiation Model ◽  
Radiation Losses ◽  
Laser Spark ◽  
Deposited Energy ◽  
Reported Data ◽  
Very High

An investigation has been done to numerically simulate the radiation losses which occur due to laser energy deposition in a domain. Although the fluid dynamic effects due to laser energy deposition has been studied by a number of researchers independently but the effect of radiation has either been neglected or has not been highlighted effectively. When laser energy is deposited in a domain, very high temperatures are reached. At such high temperature, the diatomic air species may become highly dissociated and emission from the resulting two mono atomic species N and O cannot be neglected and is the major source of radiation loss. An Open Source CFD software Open Foam has been used to study the above effects. P1 radiation model along with radiation Line by Line method has been used to calculate the radiation losses. Radiation losses obtained are20 timeshigher as compared to the only one past reported data but still are negligible as compared to the deposited energy. Hence our study validates the assumption of neglecting radiation losses, which was assumed earlier in all previous studies without any proper validation, using the most accurate LBL method.

Epitaxial Growth of AlN Thin Films on Silicon and Sapphire by Pulsed Laser Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Vispute ◽  
H. Wu ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Breakdown Field ◽  
Transmission Electron ◽  
Uv Visible ◽  
Relationship Of

ABSTRACTAIN thin films have been grown epitaxially on Si(111) and Al2O3(0001) substrates by pulsed laser deposition. These films were characterized by FTIR and UV-Visible, x-ray diffraction, high resolution transmission electron and scanning electron microscopy, and electrical resistivity. The films deposited on silicon and sapphire at 750-800°C and laser energy density of ∼ 2 to 3J/cm2 are epitaxial with an orientational relationship of AIN[0001]║ Si[111], AIN[2 110]║Si[011] and AlN[0001]║Al2O3[0001], AIN[1 2 1 0]║ Al2O3[0110] and AIN[1010] ║ Al2O3[2110]. The both AIN/Si and AIN/Al2O3 interfaces were found to be quite sharp without any indication of interfacial reactions. The absorption edge measured by UV-Visible spectroscopy for the epitaxial AIN film grown on sapphire was sharp and the band gap was found to be 6.1eV. The electrical resistivity of the films was about 5-6×l013Ω-cm with a breakdown field of 5×106V/cm. We also found that the films deposited at higher laser energy densities ≥10J/cm2 and lower temperatures ≤650°C were nitrogen deficient and containing free metallic aluminum which degrade the microstructural, electrical and optical properties of the AIN films

Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass

2016 ◽  
Vol 120 (1) ◽  
pp. 013102 ◽  
Author(s):  
Valerio Garzillo ◽  
Vytautas Jukna ◽  
Arnaud Couairon ◽  
Robertas Grigutis ◽  
Paolo Di Trapani ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Energy Deposition ◽  
Laser Energy ◽  
Single Shot ◽  
Bk7 Glass

Laser energy deposition in Edney IV interaction

Shock Waves ◽  
2005 ◽  
pp. 89-94
Author(s):  
D. Knight ◽  
R. Adelgren ◽  
G. Elliott ◽  
H. Yan ◽  
T. Beutner
Keyword(s):  
Energy Deposition ◽  
Laser Energy
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