Diameter

Inner

Outer

Drag

Buoyancy

Contact

Symbol

Di

Do

Dd

Db

Dc

Used for

(All formats)

Computing the mass/buoyancy contribution of any internal fluid

The inner diameter for stress calculations unless you specify otherwise under *PROPERTIES

The base diameter onto which any internal coatings specified with *COATINGS will be applied.

The base diameter onto which any external coatings specified with *COATINGS will be applied.

If you invoke the Distributed Buoyancy option, then the outer diameter Do is used in calculating buoyancy forces due to the structure

The effective outer diameter for hydrodynamic force evaluation using Morison’s Equation

Strictly speaking the inertia/added mass components in Morison’s Equation should be based on the buoyancy diameter (Db). This can be set under *HYDRODYNAMIC SETS with the DIAMETER=BUOYANCY tag

The effective outer diameter for buoyancy force calculations

If you invoke the Distributed Buoyancy option, then the difference between the buoyancy diameter Db and the outer diameter Do, is used in calculating buoyancy forces due to  the buoyancy material only

Strictly speaking the inertia/added mass components in Morison’s Equation should be based on the buoyancy diameter (Db). This can be set under *HYDRODYNAMIC SETS with the DIAMETER=BUOYANCY tag

The effective diameter for contact calculations (guide surface contact, line clashing or pipe-in-pipe contact)

Optionally used for seabed contact under *SEABED PROPERTIES

The diameter of elements displayed in the Model View

Additionally Used For

(Rigid Riser Format)

Used for computing cross-section area, moment of inertia and polar moment of inertia, if these are not specified directly

Used for computing cross-section area, moment of inertia and polar moment of inertia, if these are not specified directly

The outer diameter for stress calculations unless you specify otherwise under *PROPERTIES

The diameter used for CLEAR if not specified otherwise under *PROPERTIES or explicitly specified in the clear analysis input

Additionally Used For

(Flexible Riser Format)

The outer diameter for stress calculations unless you specify otherwise under *PROPERTIES

The diameter used for CLEAR if not specified otherwise under *PROPERTIES or explicitly specified in the clear analysis input

Default Value (Rigid Riser Format)

0.0

Required Input

Outer Diameter (Do)

Outer Diameter (Do)

Max(Db, Dd, Do)

Default Value (Flexible Riser Format)

0.0

Required Input (for limited cases only)

0.0

0.0

Max(Db, Dd, Do)