Calculate Morison's equation wave and current loads and lateral stability of cylinders resting on the seabed for Airy, Stokes and cnoidal waves.
Calculate lateral stability and wave loads for circular pipelines and tubulars, or for a user defined cross section. Wave velocity and acceleration can be calculated (Airy, Stokes or Cnoidal wave), or user defined. Wave spreading accounts for wave "choppiness". Vertical wave velocity and acceleration are ignored. Tipping of the structure is not included in the calculation (tipping is dependent on the structure geometry and is not normally a problem for pipelines).
Lateral stability is calculated as the ratio of horizontal force over friction force. The stability ratio should be less than or equal to one. The minimum stabilty ratio is assumed to occur between 0 and 90 degrees phase angle. The phase angle for minimum stability is calculated to the nearest degree. The Keulegan Carpenter number is calculated at the wave phase angle.
Use the Result Plot option to display either the wave profiles versus phase angle, wave velocity versus phase angle, wave loads versus phase angle, or stability factor versus phase angle.
Wave and current heading is measured relative to the structure. A relative heading of zero degrees is parallel to the structure, or ninety degrees is perpendicular to the structure.
Tool Input
- schdtype : Line Pipe Schedule Type
- diamtype : Line Pipe Diameter Type
- ODu : User Defined Outside Diameter
- IDu : User Defined Inside Diameter
- wtntype : Line Pipe Wall Thickness Type
- tnu : User Defined Wall Thickness
- wltype : Structure Weight And Dimensions Type
- Axu : User Defined Section Area
- OODu : User Defined Outer Diameter
- wu : User Defined Submerged Weight
- SGu : User Defined Specific Gravity
- hwtype : Angle Type
- Φwu : User Defined Wave Heading
- sfactype : Shape Type
- su : User Defined Spreading Factor
- rdtype : Reduction Factor Type
- Rwu : User Defined Wave Reduction Factor
- Rcu : User Defined Current Reduction Factor
- uctype : Current Velocity Type
- roughtype : Seabed Roughness Type
- zou : User Defined Seabed Roughness
- lttype : Wave Parameter Type
- Tu : User Defined Wave Period
- Lu : User Defined Wave Length
- wavetype : Wave Type
- phasetype : Wave Phase Type
- Θu : User Defined Phase Angle
- WTi : Pipe Liner Wall Thickness
- ρi : Pipe And Liner Density
- WTo : Pipe Coating Wall Thickness
- ρo : Pipe Coating Density
- C : Load Coefficients
- Φs : Structure Absolute heading
- ρc : Contents Fluid Density
- ρe : Displaced Fluid Density
- μf : Lateral Friction Factor
- d : Water Depth
- H : Wave Height
- Vr : Reference Velocity
- zr : Reference Height Above Seabed
Tool Output
- Θ : Wave Phase Angle
- Φw : Wave Heading Relative To Structure
- η : Wave Profile Height Relative To Sea Level
- Ah : Wave Horizontal Acceleration
- Ax : Structure Cross Section Area
- Fd : Drag Load
- Ff : Maximum Lateral Friction Force
- Fl : Lift Load
- Fm : Inertia Load
- Fr : Residual Lateral Friction Force
- Fx : Horizontal Wave And Current Load
- Fx/Ff : Stability Factor (< 1)
- Fz : Net Vertical Weight Load (Weight Minus Lift)
- Kc : Keulegan Carpenter Number
- L : Wave Length
- OOD : Pipe Outer Diameter Including Coatings
- Rc : Current Velocity Reduction Factor
- Rw : Wave Velocity Reduction Factor
- SG : Pipe Specific Gravity Relative To Displaced Fluid
- T : Wave Period
- Vc : Current Velocity
- Vh : Wave Horizontal Velocity
- Vx : Total Horizontal Velocity
- Ws : Pipe Total Weight Per Length Including Contents and Buoyancy
- cvg : Convergence Check
- cw : Wave Celerity
- sf : Wave Spreading Factor
- w : Wave Trough Height Above Seabed
- zo : Seabed Roughness