1. Main riser line specification 1.1. Data group identifier, one input line The main riser line (MRL) may be used to define continuous contents of several lines. This data group may be given for AR-systems only. Only one riser system may be defined on the INPMOD input file. MAIN RISEr LINE Main riser line definition, one input line MRL-ID LINE-ID1 ... LINE-IDn MRL-ID: character(8): Main riser line identifier LINE-ID1: character(8): Reference to line identifier LINE-ID1 = First line in MRL By default the MRL is defined from end 1 to end 2 of this line If the line ID is given subsequent to a minus sign, -LINE-ID1, the MRL is defined from end 2 to end 1 of this line … LINE-IDn: integer: A MRL may consist of up to 200 lines. A maximum of 5 MRLs may be defined. Main riser line flow, one input line RHOI IEND PRESSI DPRESS VVELI RHOI: real, default: 0: Density of contents \(\mathrm {[M/L^3]}\) IEND: integer: IEND=1: Pressure specified at end 1 IEND=2: Pressure specified at end 2 PRESSI: real, default: 0: Pressure at end IEND \(\mathrm {[F/L^2]}\) DPRESS: real, default: 0: Pressure drop \(\mathrm {[F/L^3]}\) VVELI: real, default: 0: Fluid velocity \(\mathrm {[L^3/T]}\) RHOI will be used to calculate weight and mass for static and dynamic analyses. The pressure drop is assumed to be uniform over the line length. For further clarification of pressure definition, please see the Theory Manual. If a nonzero pressure expansion coefficient is specified for the cross-section, the stress-free element lengths will depend on the internal pressure. Otherwise, the parameters IEND , PRESSI, DPRESS and VVELI will only be used for calculating wall force (flange force) for use in OUTMOD. An illustration is shown the figure `Main riser line concept' below with corresponding input data. Figure 1. Main riser line concept Input using the main riser line concept is shown below. '********************************************************************** ARBITRARY SYSTEM AR '********************************************************************** 'nsnod nlin nsnfix nves nricon nspr nakc 3 2 3 0 0 0 0 'ibtang zbot ibot3d 0 -1.000000000e+03 0 'B 6.5: LINE TOPOLOGY DEFINITION 'lineid lintyp-id snod1-id snod2-id line1 ltyp1 node1 node2 line2 ltyp1 node3 node2 'FIXED NODES ' .. . ... . '********************************************************************** MAIN RISER LINE '********************************************************************** 'IMRL LINE-ID(i) MRL1 line1 -line2 'rhoi iend pressi dpress 5.000000000e-01 1 1.000000000e+03 0.000000000e+00 '********************************************************************** NEW COMPONENT CRS0 '********************************************************************** . .. ... Local element axis Elastic contact surface