scholarly journals Prediksi Hambatan Kapal dengan Menggunakan Metode Overset Mesh pada Kapal Planing Hull

2020 ◽  
Vol 4 (1) ◽  
pp. 24-34
Author(s):  
Abubakar Fathuddiin ◽  
Samuel Samuel ◽  
Kiryanto Kiryanto ◽  
Aulia Widyandari
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Volume Of Fluid ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Ship Resistance ◽  
High Speeds ◽  
Mesh Method ◽  
Reynolds Averaged Navier Stokes ◽  
Volume Method

ABSTRAKPrediksi hambatan kapal tipe planing lebih rumit dibanding dengan tipe displacement, hal ini disebabkan oleh gaya hidrodinamis yang lebih dominan pada bagian bawah kapal. Karakteristik hambatan kapal tipe planing sangat dipengaruhi oleh gerakan trim dan heave. Selain itu, bentuk hullform juga mempengaruhi hambatan kapal; seperti sudut dead-rise, chine, strip, stephull, dan lain-lain. Solusi untuk memprediksi hambatan kapal dengan menggunakan Finite Volume Method (FVM). Persamaan RANS (Reynolds- Averaged Navier-Stokes) dengan model turbulensi k-ε untuk memprediksi aliran turbulen dan Volume of Fluid (VOF) untuk mempresentasikan aliran 2 fasa. Pada penelitian ini digunakan metode overset mesh untuk memprediksi hambatan kapal agar mendapatkan akurasi yang baik. Hasil simulasi hambatan menunjukkan trend yang baik. Pada kecepatan tinggi, prediksi hambatan tidak memiliki hasil yang baik. Solusi yang ditawarkan pada Numerical ventilation problem (NVP) adalah dengan menggunakan metode phase replacement.Kata kunci: CFD, planing hull, RANS, overset mesh, NVP ABSTRACTThe prediction of planing hull resistance is more complicated than the displacement hull. It is caused by the more dominant hydrodynamic force at the bottom of the ship. The planing hull resistance characteristics are strongly influenced by trim and heave movements. In addition, the shape of the hullform also affects the ship's resistance, such as dead-rise angle, chine, strip, stephull, and others. The solution to predict ship resistance is by using the Finite Volume Method (FVM). RANS (Reynolds-Averaged Navier-Stokes) equation k-ε turbulence model was used to predict turbulent flow and Volume of Fluid (VOF) to present 2 phase flow. In this study, the overset mesh method was used to predict ship resistance in order to get good accuracy. Resistance simulation results showed a good trend. At high speeds, the prediction of resistance did not have good results. The solution offered in the Numerical ventilation problem (NVP) was to use the phase replacement method.Keywords: CFD, planing hull, RANS, overset mesh, NVP

scholarly journals Simulasi CFD pada Kapal Planing Hull

Kapal ◽  
2019 ◽  
Vol 16 (3) ◽  
pp. 123-128 ◽  
Author(s):  
Samuel Samuel ◽  
Andi Trimulyono ◽  
Ari Wibawa Budi Santosa
Keyword(s):  
Froude Number ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Volume Of Fluid ◽  
Navier Stokes ◽  
Reynolds Averaged Navier Stokes ◽  
Volume Method

Akurasi dalam memprediksi hambatan kapal adalah salah satu aspek penting dalam mendesain lambung kapal. Secara umum, hambatan kapal dengan type planing lebih rumit daripada type displacement. Planing hull memiliki karakteristik unik seperti trim, heave, hard-chine, Froude number tinggi dan dead-rise angle. Gaya hidrodinamik pada planing hull lebih dominan daripada gaya hidrostatik. Analisis numerik menggunakan Finite Volume Method (FVM) dipilih untuk menyelesaikan masalah hidrodinamik. Dalam penelitian ini, persamaan (RANS Reynolds-Averaged Navier-Stokes) digunakan untuk menggambarkan model turbulensi dengan k-ε. Secara umum, pemodelan Volume of Fluid (VOF) menggunakan aliran multiphase Euler yang diasumsikan air dan udara sebagai phase. Tujuan dari penelitian ini adalah untuk memperkenalkan perhitungan kapal type planing hull untuk memprediksi hambatan kapal dan seakeeping. Studi validasi ini dilakukan dengan menggunakan eksperimen Fridsma hullform. Hasil pada penelitian ini menunjukkan bahwa simulasi numerik pada jenis planing hull dapat diprediksi dengan akurasi yang cukup baik.

Numerical Calculation on Vortex-Induced Vibration of the Circular Cylinder Using Low Reynolds Model in Hybrid Method

2009 ◽  
Author(s):  
Xingwei Zhang ◽  
Chaoying Zhou
Keyword(s):  
Numerical Calculation ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Turbulence Model ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Vortex Induced Vibration ◽  
Mesh Method ◽  
Volume Method

Fundamental research on interaction between flow and structure is presented for computation the fluid dynamics of different two-dimensional oscillating models. The Navier-Stokes equations are solved using finite volume method. A multigrid mesh method which was applied to the situation of flow past the stagnating or vibrating cylinder is developed to simulate this type of flow. The interactive results between flow and structure rigid cylinders have been present. The computation fluid dynamic codes mainly with low Reynolds RANS solver are used to solve the impressible viscous Navier-Stokes equations. Finite volume method which is coupled with conformal hybrid mesh method is developed to simulate this type of flow. Numerical investigation focused on the response and the fluid forces on the cylinders and also observed the different shedding model in the wake. The numerical results are compared in detail with recent experimental and computational work. Present numerical comparison also showed that solution using different turbulence model will make the result have a little discrepancy and each turbulence model has respective characteristics in numerical solution on the vortex-induced vibration of the cylinder. In addition, the formation of the 2P vortex shedding model through the lock-in region and the beginning of the shedding model transformation in numerical calculation from 2S model to 2P model has been analyzed.

scholarly journals Simulation of free-surface flow in a tank using the Navier-Stokes model and unstructured finite volume method

2005 ◽  
Vol 219 (3) ◽  
pp. 251-266 ◽  
Author(s):  
X Zhang ◽  
N M Sudharsan ◽  
R Ajaykumar ◽  
K Kumar
Keyword(s):  
Free Surface ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Free Surface Flow ◽  
Offshore Structures ◽  
Surface Flow ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Volume Method ◽  
Unstructured Finite Volume Method

Modelling free-surface flow has very important applications in many engineering areas such as oil transportation and offshore structures. Current research focuses on the modelling of free surface flow in a tank by solving the Navier-Stokes equation. An unstructured finite volume method is used to discretize the governing equations. The free surface is tracked by dynamically adapting the mesh and making it always surface conforming. A mesh-smoothing scheme based on the spring analogy is also implemented to ensure mesh quality throughout the computaiton. Studies are performed on the sloshing response of a liquid in an elastic container subjected to various excitation frequencies. Further investigations are also carried out on the critical frequency that leads to large deformation of the tank walls. Another numerical simulation involves the free-surface flow past as submerged obstacle placed in the tank to show the flow separation and vortices. All these cases demonstrate the capability of this numerical method in modelling complicated practical problems.

scholarly journals SIMULASI NUMERIK FENOMENA SINGLE DROPLET MENGGUNAKAN METODE VOLUME HINGGA DAN FRONT-TRACKING

POROS ◽  
2018 ◽  
Vol 15 (2) ◽  
pp. 84
Author(s):  
Dondi Kurniawan ◽  
Eko Budiana ◽  
Deendarlianto Deendarlianto ◽  
Indarto Indarto
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Stokes Equations ◽  
Initial Step ◽  
Front Tracking ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equation ◽  
Front Tracking Method ◽  
Volume Method

Abstract: A numerical simulation of single droplet phenomena is conducted using a finite volume method. Interface between different phases is tracked by using a front-tracking method. Governing equations used in present paper consist of the continuity equation, the Navier-Stokes equation and the front-tracking equation. The unsteady Navier-Stokes equations are solved implicitly using the finite volume method on staggered mesh. The interfacial term such as surface tension is negligible and the viscosity of the fluid is considered equal. The completion of pressure term is solved by Successive Over-Relaxation (SOR) method. The validation of present paper result is conducted by comparing to Tryggvasson (2012) result using explicit scheme. The advantage of this research is using implicit scheme that is unconditional stable. This research is the initial step to model a single droplet impact on solid surface. In this research will be discussed representation of interface and dynamics of interface reconstruction. Finite volume and front-tracking methods are expected to perform the problem well for more complete case. 

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