Ansys AQWA는 아래와 같은 이론을 기반으로 합니다

3D Potential Theory solution

• Ideal fluid, irrotational, incompressible
• Small wave elevation
• Viscous forces are not taken into account

Boundary condition problem is solved by satisfying

• Body Boundary condition
• Linearized free surface condition
• Sea bed boundary condition
• Radiation condition
• Solution for diffracted and radiated wave potentials uses a pulsating source distribution (zero speed solution with forward speed corrections)
• Theory applies to finite depth and diffraction problem is solved in frequency domain
• Shallow water solution is available
• Both 1st Order and 2nd Order wave forces are calculated
• 2nd Order forces can be calculated from either near field or far field solutions

Ansys AQWA 제품군

Hydrodynamic Diffraction

• Hydrodynamic Diffraction은 Frequency Domain기반의 해석 모듈로 부유체에 대한 정수상태의 다양한 정보(무게중심 / 부력중심 / 복원력 / 부피 / 메타센터 길이 등)를 계산할 수 있습니다

Hydrostatic Results

• Wave Frequency에 따른 부유체의 RAO 계산이 가능합니다(RAO Vs. Frequency). 이를 통해 특정 주파수의 파도에 대한 방향 별 부유체의 Natural Frequency를 확인할 수 있습니다

방향 별 RAO 결과

• Ansys Mechanical과 연계하여 파랑하중을 고려한 구조응답을 계산할 수 있습니다

AQWA 해석 결과

• AQWA – Mechanical Coupling System

Load Mapping한 구조 해석 결과

Hydrodynamic Response

• Hydrodynamic Response는 Frequency Domain의 해석 결과를 기반으로 한 Time Domain 해석이 가능합니다. 부유체의 평형상태해석(Stability Analysis), 시간응답해석(Time Response Analysis), 주파수통계해석(Frequency Statistical Analysis)이 가능합니다.

Hydrodynamic Diffraction(Frequency Domain)과 Hydrodynamic Response(Time Domain)

Ansys AQWA 주요기능

Articulation

• 서로 다른 바디간의 인터페이스를 구현할 수 있는 Fender는 구조해석의 접촉 조건과 같이 사용될 수 있습니다

Omni-Directional Fender / Uni - Directional Fender

[Fender 활용 사례]

• Joint를 활용하면 서로 다른 구조간의 다양한 관절 조건을 구현할 수 있습니다

Ball and Socket Joint / Universal Joint / Hinged Joint / Rigid Joint

• Mooring Line을 활용하면 부유체의 계류 효과 뿐만 아니라 계류 시스템 설계를 할 수 있습니다

Tension Leg 구현 / 복잡한 케이스 설계 / Spar 계류 모델링

Diffraction Analysis

• Hydrostatic Results
• Multiple structures including hydrodynamic interaction
• Hydrodynamic coefficients(added mass and damping)
• RAOs
• Drift coefficients (Near / far field full QTF matrix)
• Shear Force / Bending Moment Splitting forces
• Pressure distribution for transfer to structural model

Equilibrium and Stability

• Computes static equilibrium position for multiple environmental and mooring configurations
• Preliminary mooring design
• Calculates static / dynamic stability

Frequency Domain

• Significant motions at low frequency/wave frequency in frequency domain
• Permits rapid analysis using linearized parameters of mooring systems
• Graphs for response spectra / RAOs & other parameters
• Wave spreading and 2D spectra

Time Domain

• Time-history analysis of multiple structures with irregular waves
• Can use full QTF matrix for shallow water conditions
• Import of wave height time history
• Input of forces via user-defined .dll
• Output of motions and forces
• Graphical and animation results

Large amplitude motions

• Non-linear time-history analysis with large (survival) waves
• Regular or irregular waves
• Integration of pressure over wetted surface
• Standard plus sharp crested wave option

Cable dynamics

• Additional cost item for more rigorous simulation of mooring line behaviour
• Provides full coupled vessel/mooring line analyses

Excel Interface

• AQWA specific functions add-in for Excel for data and results retrieval, processing and report generation

환경 하중 조건

Regular Waves1

• Airy Waves
• Stokes 2nd-Order Waves

Multi-Directional Wave Spectrum

• Pierson-Moskowitz (PM) spectrum
• JONSWAP spectrum
• Gaussian
• User-defined spectrum
• Cross Swell

Wind

• Uniform wind
• Ochi and Shin wind spectrum
• API wind spectrum
• NPD wind spectrum
• User-defined wind spectrum

Current

• Uniform velocity current
• Velocity profiled current