• The Research Journal of the Costume Culture
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• v.30 no.6
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• pp.814-827
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• 2022

This study examines the social and artistic aspects of the Netherlands in the 16th century, focusing on the paintings of Pieter Bruegel the Elder (1525-1569), a repre- sentative Dutch painter at that time. Also analyzed were the types and characteristics of each item of the male populace's and nobles' costumes at that point in the Renaissance. The results are as follows: most of the populace's chemises do not have frills on the neckline and sleeves; the doublet has a loose body and sleeves overall; and the sleeves and armholes are fixed with sewing rather than being detachable, making the epaulet invisible. The neckline of the doublet usually does not have a collar, but it sometimes has a hood. In the case of trousers, most males are shown wearing waist-high stockings, and a piece of cord is visible. It seems that the populace's coats were mainly Spanish-style capes. The 16th-century Dutch populace's costumes are imitative-reflecting a desire to emulate the codpieces and hairstyles of the aristocrats-while providing individuality through hats and belts. In terms of practicality, it appears that a knife and pouch were used in various living environments. This trend can be seen as a reflection of populace's perception of the costume at the time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.11
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• pp.1066-1072
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• 2009

A panel method based on potential flow theory is developed for the steady/unsteady aerodynamic analysis of arbitrary three-dimensional Blended Wing Body aircraft. The panel method uses the piecewise constant source and doublet singularities as a solution. This potential based panel method is founded on the Dirichlet boundary condition and coupled with the time-stepping method. The present method uses the time-stepping loop to simulate the unsteady motion of the aircraft. The present method can solve the three-dimensional flow over the complex bodies with less computing time and provide various aerodynamic derivatives to secure the stability of Blended Wing Body aircraft. That will do much for practical applications such as aerodynamic designs and analysis of aircraft configurations and flight simulation.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.105-115
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• 2010

This technical paper describes and summarizes the flight test results for the longitudinal and lateal-directional dynamic stability characteristics. The target aircraft is the 4-seat carnard type aircraft, FireFly, which has been developed by KARI. Airborne sensors and real-time telemetry system are constructed to obtain the flight test data. The dynamic stability characteristics should be analyzed and tested by estimaitng the aerodynamic parameters in the dymaic equations of motion. The maximum likelihood estimation technique has been applied to the flight data from chirp, 3211, and doublet control inputs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.638-642
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• 2008

Computational methods based on the solution of the flow model are widely used for the analysis of lowspeed, inviscid, attached-flow problems. Most of such methods are based on the implementation of the internal Dirichlet boundary condition. In this paper, the time-domain panel method uses the piecewise constant source and doublet singularities. The present method utilizes the time-stepping loop to simulate the unsteady motion of the rotary wing blade. The wake geometry is calculated as part of the solution with no special treatment. To validate the results of aerodynamic characteristics, the typical blade was chosen such as, Caradonna-Tung blade and present results were compared with the experimental data and the other numerical results in the single blade condition and two blade condition. This isolated rotor blade model consisted of a two bladed rotor with untwisted, rectangular planform blade. Computed flow-field solutions were presented for various section of the blade in the hovering mode.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.1-8
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• 2020

The aeroservoelastic analysis that deals with the interactions of the inertial, elastic, and aerodynamic forces and the influence of the control system have been performed. MSC Nastran was used for the free vibration analysis of the structure model as the pre-analysis. ZAERO was used to calculate the unsteady aerodynamic forces. The unsteady aerodynamic forces were verified by comparing with Doublet Hybrid Method. Karpel's Minimum-State Approximation method was used for approximation of the aerodynamic forces to the Laplace domain in the frequency domain. The aeroservoelastic state-space equation was obtained by combining the aeroelastic equation with the actuator dynamics. The analysis of aeroservoelastic stability concerning the elevator input of the high aspect ratio model was performed. The root-locus method and time-integration method were used for the analysis of aeroservoelastic in frequency and time domain.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.85.2-85.2
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• 2017

The coronal electron density is a fundamental and important physical quantity in solar physics for estimating coronal magnetic fields and analyzing solar radio bursts. To check a validation of coronal electron density distributions (CEDDs) from polarized brightness (pB) measurements with Van de Hulst inversions, we compare CEDDs derived from a polarized brightness (pB) observation [MLSO/MK4 coronameter] and one spectroscopic observation [SOHO/UVCS]. For this, we consider data observed in 2005 with the following conditions: (1) the observation time differences from each other are less than 1 minutes; and (2) O VI doublet (O VI $1031.9{\AA}$ and $1037.6{\AA}$) is well identified. In the pB observation, the CEDDs can be estimated by using Van de Hulst inversion methods. In the spectroscopic observation, we use the ratio of radiative and collisional components of the O VI doublet to estimate the CEDDs. We find that the CEDDs obtained from pB measurements are higher than those based on UVCS observations at the heights between 1.6 and 1.8 Rs (${\times}1.9$ for coronal streamer, 1.2 ~ 1.8 for background corona, and 1.5 for coronal hole), while they are lower than those based on UVCS at the heights between 1.9 and 2.6 Rs (${\times}0.1{\sim}0.6$ for coronal streamer, 0.5 ~ 0.7 for background corona, and 0.6 for coronal hole). The CEDDs of coronal streamers are higher than those of background corona at the between 1.6 and 2.0 Rs: ${\times}1.2{\sim}2.4$ for MK4 and 1.5 ~ 1.9 for UVCS.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.1
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• pp.22-27
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• 2006

The linear and nonlinear aeroelastic analyses of a flat plate wing with flaperon have been performed by using frequency-domain and time-domain analyses. Natural modes from free vibration analysis and a doublet-hybrid method (DHM) are used for the computation of subsonic unsteady aerodynamic forces. The flaperon hinge is represented by a free-play spring and is linearized by the described function method. The linear and nonlinear flutter analyses indicate that flapping mode of the flaperon, the hinge stiffness and free-play of hinge have significant effects on the aeroelastic characteristics. From the nonlinear flutter analysis, different modes like stable and unstable limit-cycle-oscillation are observed in same flutter velocity depending on initial conditions.

• Selected Papers of The Society of Naval Architects of Korea
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• v.2 no.1
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• pp.1-17
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• 1994

For a planar curve-sided panel with constant or linear density distributions of source or doublet in the singularity methods, Cantaloube and Rehbach show that the surface integral can be transformed into contour integral by using Stokes'formulas. As an extension of their formulations, this paper deals with a planar polygonal panel for which we derive the closed-forms of the potentials and the velocities induced by the singularity distributions. Test calculations show that the analytical evaluation of the closed-forms is superior to numerical integration (suggested by Cantaloube and Rehbach) of the contour integral. The compact and explicit expressions may produce accurate values of matrix elements of simultaneous linear equations in the singularity methods with much reduced computer time.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.22-25
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• 2006

Direct simulations of aerodynamic sound, especially sound emitted by rapidly rotating elliptic cylinder by the finite difference lattice Boltzmann method (FDLBM). Effect of pile-fabrics for noise reduction is also studied by the finite volume LBM (FVLBM) using an unstructured grid. Second order time integration and third order upwind scheme are shown to be enough for these simulations. Sound sources are detected to be doublets for both cases. For the elliptic cylinder, the doublet is generated in the interaction between the vortex and the edge. For the circular cylinders, they are generated synchronizing with the Karman vortex street, and it is also shown that the pile-fabrics covering the surface of the cylinder reduces the strength of the source.

• Journal of ILASS-Korea
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• v.15 no.3
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• pp.109-114
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• 2010

The implementation of gelled propellants systems offers high performance, energy management of liquid propulsion, storability, and high density impulse of solid propulsion. The present study focused on the macroscopic spray characteristics of liquid sheets formed by triplet impinging jets of non-Newtonian liquids which are mixed by Carbopol 941 0.5%wt. The results are compared to experiments conducted on spray images which formed by triplet impinging jets concerning with airassist effect at center orifice. When gel propellants are injected by doublet impinging jets at low pressure and high pressure, closed rim pattern shape appeared by polymeric effect from molecular force and showed inactive atomization characteristics, because of extensional viscosity related by restriction of atomization process and breakup time delay of turbulence transition. As increasing mass flow rate of the air(increasing GAR), spray breakup level is also increased.