• 대한조선학회논문집
• /
• 제41권5호
• /
• pp.28-33
• /
• 2004

Generally Horn-type rudders have been used for single propeller and single rudder system. The reason is that the rudder torques of Horn-type rudder are smaller than those of Spade rudder with same lift force. But it is found that the rudder cavitation occurs on a Horn-type rudder of fast container ship. In this paper the comparison results of Horn-type and Spade rudders are described. HPMM tests are carried out to compare the effects of two rudder types on the maneuverability of a ship. It is shown that the maneuvering performance of a ship equipped with Horn-type rudder is better than that equipped with Spade rudder by comparing the test results and maneuvering coefficients at scantling condition. The reason is that the movable part area of Horn-type rudder is about 14％ larger than that of Spade rudder with same total area. And the rudder torque of Spade rudder is greater than that of Horn rudder. At ballast condition, however, the effect of rudder type is negligible.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
• /
• pp.316-320
• /
• 2004

This paper describes Ka-band antenna performance analysis of COMS satellite. The key parameters of the antenna system are optimal antenna diameter, feed horn type and horn size, F/D, and the coordinate of offset horns. The paper deals with the method to determine design core parameters of optimal antenna diameter, feed horn type and horn size, F/D, and the coordinate of offset horns, and the performances of design result.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제25권4호
• /
• pp.58-66
• /
• 2020

Since the typical horn-type ultrasonic equipment induces a reaction at the probe tip, the sonochemical reaction has a limitation that it occurs only in a specific area. As one of the ways to overcome this limitation, an ultrasonic device with multi-stepped horn equipped with several oscillators has been developed. The objective of this study was to investigate the sonochemical effects induced by acoustic cavitation system in 20 kHz multi-stepped ultrasonic horn using calorimetry, KI dosimetry and the luminol test. The sonochemical effects of multi-stepped ultrasonic horn were compared with that of the typical horn-type 20 kHz ultrasonic device. The effect of immersion depth and power on the sonochemical reaction was investigated in the ultrasonic system with multi-stepped ultrasonic horn. Higher calorimetric energy was obtained at higher immersion depth and power conditions. Sonochemical effects increased significantly when using the high immersion depth and input power. However, as the input power increased, the cavitation reaction zone concentrated around the ultrasonic horn. Additionally, the experiments to examine the effect of liquid temperature was conducted. The smaller sonochemical reaction was obtained for the higher liquid temperature. The effect on temperature seems to be closely related to liquid conditions such as viscosity and vapor pressure of water.

• 전기전자학회논문지
• /
• 제16권3호
• /
• pp.173-176
• /
• 2012

본 논문에서는 평판형 방사소자를 이용한 새로운 원형편파용 혼 안테나를 제안한다. 본 안테나는 평판형 마이크로스트립 안테나와 구형 혼으로 구성되며, 혼 내부에 삽입되는 마이크로스트립 안테나는 혼에 전력신호를 여기하는 급전부이자 편파기로서 동작한다. 또한, 마이크로스트립 안테나는 고이득, 높은 고립도 특성과 함께 광대역을 구현하기 위하여 금속 스페이서를 삽입한 적층형 구조로 설계되었다. 제안된 구조를 통하여, 혼 안테나는 급전부와 편파기와 같은 부가적인 구조를 별도로 설계하지 않음으로써 안테나의 소형화를 도모할 수 있다. 제안된 안테나는 8.6dBi의 이득과 4.8%의 3-dB 축비 대역폭을 가지며, 특히, 높은 대역에서 원형편파로 동작되는 이동통신 및 위성통신 분야의 다양한 안테나 시스템에 적용될 수 있다.

• 한국통신학회논문지
• /
• 제21권8호
• /
• pp.2099-2108
• /
• 1996

The performance of the E-plane monopulse feeder is shown to e improved by using corrugated horn and multimode design. The proposed multimode corrugated horn is analyzed by the mode matching technique. an E-plane monopulse feeding horn is designed and fabricated to show the performance of the multimode corrugated horn. The experiment agrees quite well with the thoretical analysis. The results can be used in the design of monopulse type tracking radar antenna.

• 공업화학
• /
• 제20권3호
• /
• pp.322-328
• /
• 2009

Octamethylcyclotetrasiloxane (OMCTS)을 에멀젼 상태에서 초음파를 조사하여 polydimethylsiloxane (PDMS)을 중합하였다. 중합에 활용된 초음파 반응기는 주파수가 20 KHz의 horn 유형과 40 KHz의 bath 유형이었으며, horn과 bath를 혼용한 경우의 중합 공정의 특성도 평가해 보았다. 고려된 주요 변수들은 반응 온도와 초음파 조사 시간 이었으며, 중합물에 대하여 각 시료의 고유 점도와 전환율 측정을 통하여 각 중합공정의 효율성과 특성을 조사하고, 최적의 공정 조건을 도출해 보고자 하였다. Horn 유형의 반응기에서는 수 분 이내에 80% 이상의 전환율이 달성되고 높은 점도의 PDMS를 얻을 수 있었으나, 조사 시간에 따라 전환율과 점도는 최대값을 보인 이후에 감소하는 경향을 나타내었다. 초음파의 강도가 상대적으로 약하게 유지되는 bath 유형의 반응기에서는 1 h 이상의 조사가 필요하였으며, horn 유형과 달리 전환율과 점도가 조사 시간에 따라 지속적으로 증가하는 경향이 지배적이었다. Horn유형과 bath유형을 조합한 혼합형 반응기에서는 다른 반응기와는 매우 다른 결과들이 나타났으며, 각 반응기의 특성은 전산 모사를 이용한 반응기 내의 음파 해석을 바탕으로 설명되었다.

• 대한기계학회논문집B
• /
• 제33권11호
• /
• pp.924-931
• /
• 2009

The two-dimensional turbulent flow around the horn-type rudder has been examined in the present study by using the commercial code FLUENT. The standard ${\kappa}-{\epsilon}$ model is used as a closure relationship. The geometry of horn rudder is based on the NACA 0020 airfoil. The simulations for various angle attack (${\alpha}$) and yaw angle(${\delta}$) are carried out. The effect of Reynolds number is also investigated in this study. The cavitation is more possible when the yaw angle is $6^{\circ}$ and it is more serious as Reynolds number increases.

• International Journal of Aeronautical and Space Sciences
• /
• 제5권2호
• /
• pp.71-76
• /
• 2004

This paper describes the antenna analysis of the multi-beam for communicationsatellite. The design core parameters of the antenna system are optimal antennadiameter, feed horn type and hom size, F/D, and the coordinate of offset horns. Thepaper deals with the method to determine design core parameters of optimal antennadiameter, feed horn type and horn size. F/D, and the coordinate of offset horns, andthe performances of design result.

• 대한조선학회논문집
• /
• 제47권4호
• /
• pp.553-564
• /
• 2010

This paper studies on the rudder shapes for the suppression of the cavitation around a horn-type rudder. To improve the problems due to cavitation, there have been several studies. However, these some studies are recognized as incomplete ways to suppress the rudder cavitation. In this study, the section shapes to suppress the cavitation phenomena are determined by moving the location of maximum thickness for reducing the curvature variation and changing the radius of leading edge. Also, in the pintle part, the curvature radius of the inlet outlet edge of rudder plate is changed. During the design of rudder shape, two-dimensional numerical simulations are firstly performed because those offer some advantages with that cavitation phenomena becomes predictable for a short time, and then the three-dimensional numerical simulations are performed to confirm the determination. The time mean distribution of the propeller slipstream is imposed on the inlet boundary condition. As some results, this paper shows the effects reducing the range of the occurrence of cavitation, and suggests the references on the design of a horn-type rudder for the suppression of cavitation phenomena.

• 대한조선학회논문집
• /
• 제48권4호
• /
• pp.346-356
• /
• 2011

Rudder is to be located in extremely complicated flows generated and disturbed behind a hull and a propeller in operation. In order to estimate the rudder efficiency, it is quite important to investigate the disturbed flows due to the interaction under the hull-propeller and rudder condition. The purpose of the present research is to investigate the interaction between the hull-propeller and a high-lifting horn-type rudder through both numerical computations and experiments. A horn-type rudder implementing the Coanda effect of USB (Upper Surface Blowing) type is selected for its high efficiency of lifting force, and a 1/85 scaled model of 47K PC(Product Carrier) is manufactured for the purpose of the model test. The forces acting on the rudder during the experiment are measured using a three-component force gauge. Both cases are investigated in the hull-propeller-rudder condition and rudder open-water condition, which confirms that the flows generated under the former condition is considerably different from that of the latter condition.