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Core Spreading Vortex Method for Simulating 3D Flows Around Bluff Bodies Zuhal, Lavi Rizki; Dung, Duong V.; Sepnov, Alex J.; Muhammad, Hari
Journal of Engineering and Technological Sciences Vol 46, No 4 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1641.249 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.4.7

Abstract

This paper presents the development of core spreading vortex element method, which is a mesh-free method, for simulating 3D viscous flow over bluff bodies. The developed method simulates external flow around complex geometry by tracking local velocities and vorticities of particles introduced within the fluid domain. The viscous effect is modeled using core spreading method coupled with the splitting spatial adaption scheme, and a smoothing interpolation scheme for overlapping issue and population control, respectively. The particle’s velocity is calculated using Biot-Savart formulation. To accelerate computation, Fast Multipole Method (FMM) is employed. The solver is validated, for both unbounded and bounded flows at low Reynolds numbers, using a number of benchmark problems. For unbounded case, simulation of the collision of two vortex rings was performed. To test the performance of the method in simulating bounded flow problem, simulation of flow around a sphere was carried out. The results are found to be in good agreement with those reported in literatures and also simulations using other diffusion model.
Linear Parameter-Varying Versus Linear Time-Invariant Reduced-Order Controller Design for Turboprop Aircraft Dynamics Widowati, Widowati; Riyanto, Bambang; Muhammad, Hari
Journal of Engineering and Technological Sciences Vol 44, No 2 (2012)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (379.994 KB) | DOI: 10.5614/itbj.eng.sci.2012.44.2.5

Abstract

The  applicability  of  parameter-varying  reduced-order  controllers  to aircraft  models  is  proposed.  A  generalization  of  the  balanced  singular perturbation method of the linear time-invariant (LTI) system was used to reduce the order of  the  linear parameter-varying (LPV) system. Based on the reducedorder model, a  low-order  LPV  controller  was  designed  using  the H∞ synthesis technique.  The  performance  of  the  reduced-order  controller  was  examined  by applying  it  to  the  lateral-directional  control  of  a  20th-order  aircraft  model. Furthermore, the time responses of the closed-loop system with  several reducedorder LPV controllers and  a  reduced-order LTI controller  were  compared.  The simulation results  show that an  ,  8th -order LPV controller can maintain stability and  provide  the  same  level  of  closed-loop  system  performance  as  a  full-order LPV  controller.  This  was  not  the  case  with  the  reduced-order  LTI  controller, which  cannot  maintain  stability  and  performance  for  all  allowable  parameter trajectories.
PREDIKSI DAN ANALISIS KESTABILAN GERAK LONGITUDINAL KAPAL BERSAYAP WING-IN-SURFACE EFFECT Muhammad, Hari
Mesin Vol 19, No 1 (2004)
Publisher : Mesin

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (302.682 KB)

Abstract

This paper discusses the stability of Wing-in-Surface-Effect (WiSE) craft. The aerodynamic parameters of new WiSE craft jointly designed by the Agency for the Assessment and Application of Technology, Indonesian Aerospace Ltd. and Institute of Technology Bandung are estimated using software Digital Datcom of the US Air Force. The aerodynamic parameters are used to predict the longitudinal stability characteristics of the WiSE craft. The surface effect on some aerodynamic parametes that influence the longitudinal stability of the WiSE craft will be discussed in this paper.
RANCANG BANGUN MICRO AIR VEHICLE KONFIGURASI TAILLESS Mulyanto, Taufiq; Wijaya, Arinta H; Muhammad, Hari
Mesin Vol 23, No 2 (2008)
Publisher : Mesin

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (9480.792 KB)

Abstract

Nowadays, Micro Air Vehicle (MAV) is mostly developed for surveillance purpose, either for military or civilian. In this article, a design and building of a MAV will be presented. A tailless configuration was chosen. The design and build process started with a study of several design parameters of existing MAVs. Then, it is followed by initial sizing, detail design and production of the MAV. In general, the designed MAV could meet the design requirements and objectives stated. Some preliminary tests had shown that the basic flying characteristics was sufficiently good, although further development still has to be done. The design and build process was also able to evaluate the implementation of some aircraft design formula and method being implemented to design MAV.
Linear Parameter-Varying Versus Linear Time-Invariant Reduced-Order Controller Design for Turboprop Aircraft Dynamics Widowati Widowati; Bambang Riyanto; Hari Muhammad
Journal of Engineering and Technological Sciences Vol. 44 No. 2 (2012)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2012.44.2.5

Abstract

The  applicability  of  parameter-varying  reduced-order  controllers  to aircraft  models  is  proposed.  A  generalization  of  the  balanced  singular perturbation method of the linear time-invariant (LTI) system was used to reduce the order of  the  linear parameter-varying (LPV) system. Based on the reducedorder model, a  low-order  LPV  controller  was  designed  using  the H∞ synthesis technique.  The  performance  of  the  reduced-order  controller  was  examined  by applying  it  to  the  lateral-directional  control  of  a  20th-order  aircraft  model. Furthermore, the time responses of the closed-loop system with  several reducedorder LPV controllers and  a  reduced-order LTI controller  were  compared.  The simulation results  show that an  ,  8th -order LPV controller can maintain stability and  provide  the  same  level  of  closed-loop  system  performance  as  a  full-order LPV  controller.  This  was  not  the  case  with  the  reduced-order  LTI  controller, which  cannot  maintain  stability  and  performance  for  all  allowable  parameter trajectories.
Core Spreading Vortex Method for Simulating 3D Flows Around Bluff Bodies Lavi Rizki Zuhal; Duong V. Dung; Alex J. Sepnov; Hari Muhammad
Journal of Engineering and Technological Sciences Vol. 46 No. 4 (2014)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2014.46.4.7

Abstract

This paper presents the development of core spreading vortex element method, which is a mesh-free method, for simulating 3D viscous flow over bluff bodies. The developed method simulates external flow around complex geometry by tracking local velocities and vorticities of particles introduced within the fluid domain. The viscous effect is modeled using core spreading method coupled with the splitting spatial adaption scheme, and a smoothing interpolation scheme for overlapping issue and population control, respectively. The particle's velocity is calculated using Biot-Savart formulation. To accelerate computation, Fast Multipole Method (FMM) is employed. The solver is validated, for both unbounded and bounded flows at low Reynolds numbers, using a number of benchmark problems. For unbounded case, simulation of the collision of two vortex rings was performed. To test the performance of the method in simulating bounded flow problem, simulation of flow around a sphere was carried out. The results are found to be in good agreement with those reported in literatures and also simulations using other diffusion model.
PREDIKSI DAN ANALISIS KESTABILAN GERAK LONGITUDINAL KAPAL BERSAYAP WING-IN-SURFACE EFFECT Hari Muhammad
Mesin Vol. 19 No. 1 (2004)
Publisher : Mesin

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This paper discusses the stability of Wing-in-Surface-Effect (WiSE) craft. The aerodynamic parameters of new WiSE craft jointly designed by the Agency for the Assessment and Application of Technology, Indonesian Aerospace Ltd. and Institute of Technology Bandung are estimated using software Digital Datcom of the US Air Force. The aerodynamic parameters are used to predict the longitudinal stability characteristics of the WiSE craft. The surface effect on some aerodynamic parametes that influence the longitudinal stability of the WiSE craft will be discussed in this paper.
RANCANG BANGUN MICRO AIR VEHICLE KONFIGURASI TAILLESS Taufiq Mulyanto; Arinta H Wijaya; Hari Muhammad
Mesin Vol. 23 No. 2 (2008)
Publisher : Mesin

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Nowadays, Micro Air Vehicle (MAV) is mostly developed for surveillance purpose, either for military or civilian. In this article, a design and building of a MAV will be presented. A tailless configuration was chosen. The design and build process started with a study of several design parameters of existing MAVs. Then, it is followed by initial sizing, detail design and production of the MAV. In general, the designed MAV could meet the design requirements and objectives stated. Some preliminary tests had shown that the basic flying characteristics was sufficiently good, although further development still has to be done. The design and build process was also able to evaluate the implementation of some aircraft design formula and method being implemented to design MAV.
SIMULASI ALIRAN FLUIDA DUA DIMENSI TANPA MEMBUTUHKAN KISI-KISI DENGAN MENGGUNAKAN METODE VORTEKS. STUDI KASUS ALIRAN DI SEKITAR SILINDER DAN PELAT DATAR YANG BERGERAK TRANSLASI (MESHLESS SIMULATION AROUND TWO DIMENSIONAL FLOW USING VORTEX METHOD. CASES STUDY: FLOW AROUND CYLINDER AND MOVING FLAT PLATE WITH TRANSLATIONAL MOTION) Akhmad Farid Widodo; Lavi Rizki Zuhal; Hari Muhammad
Jurnal Teknologi Dirgantara Vol.11 No.1 Juni 2013
Publisher : National Institute of Aeronautics and Space - LAPAN

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Makalah ini membahas algoritma metode vorteks yang merupakan metode numerik simulasi dinamika fluida tanpa membutuhkan kisi-kisi. Metode vorteks memodelkan aliran fluida dengan pendekatan Lagrangian dimana elemen fluida didiskritisasi menjadi bola-bola partikel yang bergerak mengikuti aliran fluida. Untuk menguji hasil simulasi metode vorteks, dilakukan simulasi aliran yang bergerak secara tiba-tiba disekitar silinder dan aliran disekitar pelat datar yang bergerak secara translasi. Hasil simulasi memberikan hasil yang cukup baik dibandingkan dengan pengukuran eksperimental yang ditunjukkan dengan perbandingan pola distribusi vortisitas.Kata Kunci: Metode vorteks, Simulasi tanpa kisi-kisi, Aliran di sekitar pelat datar, Aliran di sekitar silinder
METODA COROTATIONAL BEAM 2D UNTUK ANALISIS STATIK STRUKTUR NONLINIER GEOMETRIK Novi Andria; Lavi Rizki Zuhal; Leonardo Gunawan; Hari Muhammad
Jurnal Teknologi Dirgantara Vol. 17 No. 1 Juni 2019
Publisher : National Institute of Aeronautics and Space - LAPAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.jtd.2019.v17.a3117

Abstract

Makalah ini membahas sebuah metoda corotational beam dua dimensi (CBM 2D) yang dapat digunakan untuk analisis statik struktur yang nonlinier secara geometri. Kombinasi antara formulasi corotational beam dan Euler-Bernouli beam Theory (EBT) membuat implementasi numerik metoda ini menjadi sangat sederhana dengan beban komputasi yang rendah sehingga sangat praktis untuk diaplikasikan. Akurasi dan efisiensi metoda ini terverifikasi melalui beberapa uji numerik yang dilakukan pada beberapa model uji yang terdapat pada literatur. Metoda ini pun mampu memberikan hasil yang akurat untuk kasus extensible beam dan struktur beam yang dibebani follower load. Hasil penelitian ini memverifikasi validitas, efisiensi, dan kepraktisan dari metoda yang dikembangkan.