• Title/Summary/Keyword: Driving velocity

Search Result 522, Processing Time 0.024 seconds

Analysis of Airflow due to the Configuration of Automotive Diffuser (자동차 디퓨저의 형상에 따른 공기흐름의 해석)

  • Choi, Kyekwang;Cho, Jaeung
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.19 no.11
    • /
    • pp.16-22
    • /
    • 2020
  • This study was aimed at analyzing the velocity and pressure changes in the airflow corresponding to different configurations of a diffuser for three types of cars. According to the flow results of the three automotive models, in model 3, the vortex was formed slightly upward on the outlet plane, whereas in models 1 and 2, the vortex was generated lower than that in model 3. The values of the pressure distribution in model 3 were larger than those for models 1 and 2 on the planes located at the same distance from the end of the rear part. The maximum turbulent kinetic energies in models 1 and 2 occurred at a location lower than that in model 3. The shape corresponding to the airflow that enhanced the driving performance was determined through the flow analysis.

Real time measurement of an acoustic stream by a visualization technique, PIV (PIV(Particle Imaging Velocimetry)에 의한 음향류의 실시간 가시화 계측)

  • 도덕희
    • Proceedings of the Acoustical Society of Korea Conference
    • /
    • 1998.06c
    • /
    • pp.239-242
    • /
    • 1998
  • A new real time sound field visualization technique is introduced in this study using PIV(Particle Imaging Velocimetry) technique. Small particles of which density is small enough to follow up the air flow are used for sound visualization. When the driving frequency is in the vicinity of the resonance frequency of the simplified 2-dimensional muffler system, an acoustic streaming is shown and of which velocity distribution is obtained through PIV technique. It is experimentally proved that the present technique is able to visualize and quantify the sound field's energy flow.

  • PDF

Spin-stabilized platform model with two input and two output (2-입력 2-출력을 갖는 자전 안정화 플랫트폼 모델)

  • 유인억;이상정
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1996.10b
    • /
    • pp.804-807
    • /
    • 1996
  • In this paper, a new model of TDF(two degree of freedom) spin-stabilized platform has been suggested. The platform driving signal modulated in the spinning frequency is described in demodulated form keeping its precession angular velocity. When a strong spinning torque exists, the cross-axis spring constant cannot be neglected in modelling of the platform precession dynamics. A linearized dynamic model of spin-stabilized platform pointing loop is derived and validated through the comparison between simulation and experimental results.

  • PDF

A Frequency-Variable Ultrasonic Vibrator with Conical Horn for Ultrasonic Machining

  • Kim, Moo-Joon
    • The Journal of the Acoustical Society of Korea
    • /
    • v.16 no.3E
    • /
    • pp.37-43
    • /
    • 1997
  • A frequency-variable ultrasonic vibrator is designed, which is made of a multi-layered PZT vibrator with a conical horn. Transmission line equations for the conical horn are derived and analyzed using the equivalent circuit method in order to analyze the characteristics of the vibrator. The controllability of the driving characteristics by varying the electrical impedance is confirmed by the experimental results of the free admittance characteristics and the vibrational velocity distributions.

  • PDF

Signal Processing Algorithm of FMCW RADAR using DSP (DSP를 이용한 FMCW 레이다 신호처리 알고리즘)

  • 한성칠;박상진;강성민;구경헌
    • Proceedings of the IEEK Conference
    • /
    • 2001.06a
    • /
    • pp.425-428
    • /
    • 2001
  • In this paper, FMCW radar signal processing technique for the vehicle detection system are studied. And FMCW radar sensor is used as a equipment for vehicle detection. To test the performance of developed algorithm, the evaluation of the algorithm is done by simulation for signal processing technique of vehicle detection system. RADAR signal of a driving vehicle is generated by using the Matlab. Distance and velocity of vehicles are calculated with developed a1gorithm. Also the signal processing procedure is done for the virtual data with FM-AM converted noise.

  • PDF

Dynamic analysis of a launcher under impulsive forces (충격력을 받는 발사대의 동역학적 해석)

  • 이병훈;유완석;김준호
    • Journal of the korean Society of Automotive Engineers
    • /
    • v.15 no.2
    • /
    • pp.84-91
    • /
    • 1993
  • The dynamic behaviors of a launcher under impulsive forces are analyzed. All the components of the system, ie ; chassis, turret, cage and suspension parts, are modeled as rigid. The dynamic analysis code, which is developed with the formulae describing the system equations of motion in terms of relative quantities, is used to carry out the analysis. The results show the dynamic responses of chassis and cage when the driving constraints are imposed on turret and cage.

  • PDF

The traffic accident factors and reduction method in the hazard zone of mountain sightseeing roads -focused on Jeju local roads- (산악관광도로 위험구간의 교통사고 요인분석 및 감소방안 -제주도의 지방도를 중심으로-)

  • Oh, Jae-Hwan;Hwang, Kyung-Soo;Kim, Kyung-Bum;Yang, Jeong-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.1
    • /
    • pp.374-388
    • /
    • 2016
  • In Jeju-Do, there is the 1100 Road, 516 Road, and Bijarimro, which are typical mountain sight-seeing roads in Jeju. These roads are local roads that have been the location for many traffic accidents. This study focused on these roads, categorized the type of traffic accident and analyzed the accident characteristics. The major accident factors were analyzed through trip AHP analysis, Comparative analysis of the velocity distribution and the factors affecting traffic accidents were analyzed. Tourists took many trips on these roads. The mixing rate of the rental cars was 36.70%~71.60% in 1100 road and Bijarimro. Currently, these local roads are regulated by a speed limit of 60km/h. However, it might be necessary to reduce the speed limit to 40km/h considering the geometric line form of the road and the climate in these areas. The speed limit of more than 40km/h is found 87.0% on 516 Roads, 88.57% on 1100 roads, and 93.1% on Bjarimro, In these roads, the speed ratio is higher as described above. Therefore, these roads have been found to have a higher risk of traffic accidents by overspeeding driving. The overspeed driving ratio of these roads was 87.0%~93.1%, The overspeed driving enforcement method at one spot has only the effect of reducing the speed at that enforcement place; the effect cannot be expected for the other places or sections. It is necessary to introduce a section overspeed driving enforcement system utilizing the average velocity in these areas to prevent traffic accidents.

Study on Separating Performance of Oscillating Sieve in Wet-Paddy Threshing (요동(搖動)체의 벼 생탈곡물(生脱糓物) 선별성능(選別性能)에 관(關)한 연구(硏究))

  • Kim, Sang Hun
    • Journal of Biosystems Engineering
    • /
    • v.7 no.1
    • /
    • pp.33-41
    • /
    • 1982
  • When wet-paddy is threshed by conventional auto-fed thresher, the threshed material under the concave is difficult to separate with pneumatic separation only. The development of thresher with an oscillating sieve in addition to the conventional pneumatic separation has been recommanded to improve the separation of grains from straw and chaff having high moisture content. This study was intended to evaluate the separating performance of an oscillating sieve and to obtain the effective operation conditions of the sieve separation. The sieve with oscillating in an elliptical motion was developed and installed in the experimental unit which can simulate the separating operation of the conventional auto-fed thresher. Results of the study are summarized as follows: 1. The flowing velocity of grains on oscillating sieve was increased as the sieve frequency increased but the feed rate did not significantly affect the flowing velocity of grains on sieve. 2. The effects of sieve frequency and the direction of sieve rotation on the separating performance by oscillating sieve show that increasing the frequency of sieve driving crank above the 460 rpm in the same direction of material flow (con-flow) improved the separating performance. 3. The height of grain guide plate and air velocity through the sieve to optimize the separating performance of oscillating sieve were experimentally determined to give about 10cm above the sieve and 7 m/s, respectively.

  • PDF

The Effect of Track Tension on the Tractive Performance of Combine (궤도(軌道)의 장력(張力)이 콤바인의 주행(走行) 성능(性能)에 미치는 영향(影響))

  • Park, G.B.;Kim, K.U.
    • Journal of Biosystems Engineering
    • /
    • v.17 no.3
    • /
    • pp.237-246
    • /
    • 1992
  • This study was conducted to investigate experimentally the effect of track tension on the tractive performance of rice combine. The experiment was carried out at the two in-door soil bins with soil types of loam and sandy loam. The initial track tension was varied by three different values of 0.71, 1.75 and 3.84kN at three different forward velocity settings of 0.17, 0.32 and 0.45m/s, respectively. The data acquisition system was designed and used for the measurement of pull, driving axle torque and its velocity under the test conditions to calculate the tractive efficiency. Results of the study were summarized as follows : 1) The effect of the initial track tension on the tractive efficiency was found being significantly dependent on soil types but not on forward velocities. Therefore, the benifit of adjusting the initial track tension may be obtained when the types of soils on which combines operate are changed. 2) In loam, tractive efficiency decreased with increase in track tension. However, it increased in sandy loam until it reached to a peak value and then decreased with increase in track tension. 3) The maximum tractive efficiency of the tested combine was obtained with an initial track tension of about 1.75kN on sandy loam, and below that on loam at about 5% slippage without being noticeably influenced by the forward velocity.

  • PDF

Numerical Analysis on Velocity Fields around Seabed Tiller for the Improvement of Seabed Soil (해저 토질 개선을 위한 해저경운기 주변의 속도장에 대한 수치해석)

  • Kim, Jang-Kweon;Oh, Seok-Hyung;Kim, Jong-Beom;Chung, Sang-Ok
    • Journal of Power System Engineering
    • /
    • v.21 no.2
    • /
    • pp.48-56
    • /
    • 2017
  • The steady-state, incompressible and three-dimensional numerical analysis was carried out to evaluate the velocity fields around the seabed tiller used for the improvement of the seabed soil and the pulling force and buoyancy generated by driving the seabed tiller. The turbulence model used in this study is a realizable $k-{\varepsilon}$ well known to be excellent for predicting the performance of the flow separation and recirculation flow as well as the boundary layer with rotation and strong back pressure gradient. As a results, a typical vortex pair appears near the adjacent rotor vane tip. When the current is stopped, there is no force when pulling the seabed tiller, but when the current flows at 1.2 knots, the force acts on the downstream side and the pulling force is much greater. In stationary currents, the buoyancy of the seabed tiller acts more strongly towards the seabed as the number of rotations of the rotor increases, but acts more strongly toward the sea surface at 1.2 knots of current.