REVIEW 3 major objections 6 minor 33 references
Flow-induced vibration of twin-pipe model with varying mass and damping: A study using virtual physical framework
T0 review · 3 major / 6 minor · reviewed 2026-08-07 · deepseek-v4-flash
Pith's one-line read This paper claims that for a rigidly coupled tandem twin-pipe model, flow-induced vibration can persist without decay below a critical mass ratio of about 1.1, and that the effect is carried by the total added-mass coefficient stabilizing…
desk verdict Useful twin-pipe FIV dataset and a solid VPF extension, but the 'resonance forever' interpretation rests on a factor-of-two error in the critical mass ratio. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The load-bearing object is the 'virtual physical framework' (VPF): a closed-loop hybrid rig in which the twin-pipe model is a real towed structure, while the elastic support—mass $m$, stiffness $k$, damping $c$—exists only in a numerical solver. Measured cross-flow forces on the upstream and downstream pipes are fed into a recursive Duhamel integral solver that produces a displacement command executed by servo actuators; the input mass is set to $m + m_{p,\mathrm{up}} + m_{p,\mathrm{down}}$ so the physical inertial forces cancel and the realized equation of motion is exactly $m\ddot{y}+c\dot{y}+ky=F_{\mathrm{up}}+F_{\mathrm{down}}$. The force signals are then decomposed by least squares into an in-phase-with-velocity component (excitation coefficient $C_v$) and an in-phase-with-acceleration component (added-mass coefficient $C_m$); the sum of the two pipes' $C_m$ values is the quantity that carries the critical-mass argument via $m^*_{\mathrm{crit}} = -C_{m,\mathrm{total}}$.
What would settle it
A decisive check is to test twin-pipe mass ratios just above and below the claimed threshold, e.g., $m^*=1.05$, $1.15$, and $1.5$, at $U_R$ up to 30 and beyond. If sustained vibration appears at $m^*>1.1$, or if $m^*=1.0$ decays when $U_R$ is extended past 30, the transferred critical-mass explanation fails. A second check is to see whether the flat amplitude branch at $m^*=1.0$ responds to added damping: if it persists unchanged rather than shrinking, 'resonance forever' is not the right mechanism.
Extended reading notes
Core claim
On the paper's own terms, the central discovery is that a rigidly coupled tandem twin-pipe model with spacing $G/D=2$ at $\mathrm{Re}=2\times10^4$ has a mass-ratio-dependent flow-induced vibration response that extends the single-cylinder critical-mass phenomenon to a two-pipe system. As the mass ratio decreases, the synchronization region broadens, the vibration amplitude in the lower branch stays higher, and the added-mass and excitation coefficients become steadier; at $m^*=1.0$ the amplitude plateaus near $0.8D$ and does not decay even at $U_R=30$. The paper attributes this to 'resonance forever': the total added-mass coefficient of the two pipes stabilizes near $-1.1$, so the critical mass ratio is about 1.1, and $m^*=1.0$ lies below it. It also identifies an amplitude drop near $U_R=6$: the upstream and downstream pipes' excitation coefficients take opposite signs, meaning the downstream pipe dissipates energy and temporarily suppresses the response. Damping mainly lowers the amplitude and the drag coefficient, while leaving the dominant frequency and most hydrodynamic coefficients nearly unchanged; the in-line interaction between pipes is generally compressive and strengthens with mass ratio, and the torsional moment stabilizes around 0.46 at low mass ratios.
Load-bearing premise
The argument assumes that the single-cylinder rule linking the critical mass ratio to the negative added-mass coefficient, $m^*_{\mathrm{crit}} = -C_m$, applies unchanged to two rigidly connected pipes; the paper sees a total added-mass coefficient near $-1.1$ and treats that as proof that $m^*=1.0$ lies below the twin-pipe threshold, without independently testing the threshold.
Editorial extensions
If this is right
- If the critical-mass transfer is right, twin-pipe structures with $m^*$ near or below 1.1 must be designed for persistent large-amplitude vibration across a wide reduced-velocity range, turning fatigue life into a first-order design constraint.
- The amplitude drop at $U_R\approx6$ means wake and shielding rules for rigidly coupled pairs need phase-resolved models: the downstream pipe can act as a damper at some speeds, so mean-drag-only design loads will miss this transient energy sink.
- High mass ratios imply stronger compressive in-line interaction between the pipes, so connectors and truss elements must be checked for compressive hydrodynamic loads in addition to drag and lift.
- Damping is a limited design lever: it suppresses amplitude and drag, but does not shift the dominant frequency or the stabilized hydrodynamic coefficients, so adding damping will not move a twin-pipe system out of synchronization.
Reading between the lines
- My inference: the flat amplitude branch at $m^*=1.0$ could equally be a galloping or wake-induced branch; the paper's critical-mass explanation would be tested by measuring whether the branch persists when the natural frequency is detuned or when $U_R$ is pushed beyond 30.
- My inference: the same VPF rig could map the critical mass ratio as a function of spacing ratio $G/D$, since the downstream-pipe phase and added-mass contributions should change with spacing; the paper fixes $G/D=2$.
- My inference: if the total added-mass coefficient is the controlling quantity, then unequal-diameter twin pipes would have a different effective threshold computable from the same $-C_m$ rule, offering a direct extension to riser clusters.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper develops a virtual physical framework (VPF) for flow-induced vibration (FIV) experiments on a rigidly coupled tandem twin-pipe model, in which the structural mass, damping, and stiffness are implemented numerically while the hydrodynamic forces are measured physically. The framework is validated through stationary towing tests and single-pipe VIV benchmarks. Systematic experiments are then reported for mass ratios m*=1.0, 2.4, and 10.0 and damping ratios 0, 0.001, and 0.005, documenting cross-flow amplitude, dominant frequency, drag, excitation and added-mass coefficients, in-line interaction, and torsional moments. The main claims are an amplitude drop near UR=6, a total added-mass coefficient stabilizing near -1.1, and a "resonance forever" behavior at m*=1.0 attributed to a critical mass ratio of approximately 1.1.
Significance. If the VPF is reliable and the reported observations are robust, the paper provides a useful experimental dataset for a configuration that is far less studied than isolated cylinders, and the validation against published single-pipe VIV results is a definite strength. The framework itself, with its recursive Duhamel integral implementation and inertial-force compensation, is a promising experimental tool. However, the central mechanistic conclusion—that the sustained vibration at m*=1.0 is the known "resonance forever" phenomenon caused by a critical mass ratio near 1.1—is undermined by an algebraic inconsistency in the paper's own definitions, and the alternative explanations are not excluded.
major comments (3)
- [Section 4.2; Section 3.1; Eq. (13)] The inferred critical mass ratio contains a factor-of-two error. The paper defines m* = m/m_delta with m_delta = πρLD²/2, the total displaced mass of both pipes, while Eq. (13) gives the added-mass force per pipe as -(π/4)D²Lρ Cm yddot. Summing over the two rigidly coupled pipes gives a total added-mass force of -(m_delta/2)(Cm_up+Cm_down) yddot. Moving this to the left side of the equation of motion yields m*_eff = m* + Cm_total/2, so the critical mass ratio is m*_crit = -Cm_total/2. With the reported Cm_total ≈ -1.10, the corrected threshold is approximately 0.55, not 1.1. Consequently, m*=1.0 lies above the critical value, and the statement in Section 4.2 that m*=1.0 "is below the critical mass ratio" is internally inconsistent with the paper's own definitions.
- [Section 4.2] Even after correcting the factor of two, the causal explanation remains unsupported. The paper applies the single-cylinder critical-mass concept of Govardhan and Williamson (2002) to the rigidly coupled twin-pipe system without an independent test, and the fitted total Cm and the observed flat amplitude branch come from the same experimental runs, so the "prediction" is circular. The flat, non-decaying branch at m*=1.0 could equally be consistent with galloping or wake-induced vibration, which the paper cites in the introduction but does not rule out for this configuration. The authors should either provide an independent test of the critical-mass mechanism or substantially weaken the resonance-forever claim.
- [Section 4.1; Figure 7] The "resonance forever" claim is based on a finite observation window (up to UR=32) with no reported repeat runs or uncertainty bars. Since the claim is essentially that the amplitude does not decay with increasing reduced velocity, single realizations without quantification of scatter make this invariance statement difficult to assess. At minimum, the authors should report repeated trials or an uncertainty estimate for the amplitude points, and they should state explicitly that the conclusion is limited to the tested UR range.
minor comments (6)
- [Section 3.2] The text refers to the "VFS system" in the paragraph following Figure 5; this appears to be a typo for "VPF system."
- [Figure 8 caption] The caption contains the typo "dwonstream" instead of "downstream."
- [Eq. (13)] The formula for the excitation force is typeset ambiguously: the expression "1/2 sqrt(2) ˙yrms" is presumably intended to appear in the denominator of the Cv term. Please clarify the notation so that Cv is unambiguously defined.
- [Table 1] The reduced-velocity ranges are given in the notation "3:1:32" without explanation; please define this as start:increment:end or replace it with an explicit range.
- [Section 4.1 and Figure 7(a)] The text says that for m*=1.0 "there is almost no well-defined lock-in region, and the frequency gradually increases with UR," but Figure 7(a) annotates a lock-in frequency of 0.92 and the text elsewhere states that the twin-pipe model exhibits a frequency lock-in region near the amplitude drop. These statements should be reconciled.
- [Conclusion] The conclusion contains the typo "a serie of tests" instead of "a series of tests."
Circularity Check
The resonance-forever explanation is partially circular: C_m is least-squares fitted to the same FIV runs and then converted into m*_crit≈1.1, making the threshold an arithmetic restatement of the fit rather than an independent prediction.
-
fitted input called prediction
[Section 4.2, Eq. (13) and the paragraph on total added mass coefficient]
"The Cv and Cm are obtained using the least squares method based on the measured lift force. ... the sum of the stabilized added mass coefficients Cm for the two pipes remains nearly constant across different mass ratios, with values approximately −1.10 for m*=1.0 and −1.12 for m*=2.4. ... In this condition, the critical mass ratio is given by m*_crit = −Cm ... In the present twin-pipe model, the total Cm stabilizes around 1.1, indicating a critical mass ratio of approximately 1.1. The case of m*=1.0, which is below the critical mass ratio, shows the resonance forever phenomenon."
Cm is obtained by least-squares fitting Eq. (13) to the lift force measured in the same tests that exhibit the non-decaying amplitude labeled 'resonance forever'. The critical mass ratio is then set as m*_crit = -Cm, so the statement that m*=1.0 lies below the threshold is an algebraic consequence of the fitted coefficient, not an independent determination. The twin-pipe critical mass ratio is never measured by a separate bifurcation experiment; the same dataset supplies both the fit and the phenomenon it is claimed to confirm.
full rationale
The empirical amplitude plateau (A*≈0.8 up to UR=30) is a genuine measurement and is not itself circular; neither are the drag/torsion coefficient descriptions. However, the paper's central mechanistic conclusion—that twin-pipe m*_crit≈1.1 and that m*=1.0 is therefore below critical—reduces to the fit: the same measured forces are used to extract Cm, and the GW criterion is then applied to the fitted number. This is fitted-input-called-prediction rather than an independent confirmation. I find no load-bearing self-citation chain: Ren et al. (2024) is used for the delay-compensation method and Shen et al. (2024) for a similar amplitude drop, but the critical-mass argument rests on an external GW concept. Separately, and this is a correctness rather than circularity issue, the paper's own definitions imply m*_crit = -C_m,total/2 ≈ 0.55 rather than 1.1, because m∆ is the two-pipe displaced mass while Eq. (13) Cm is per-pipe; this would put m*=1.0 above the threshold. The score reflects partial circularity of the central explanatory claim, not the raw data.
Assumptions & free parameters
free parameters (2)
- Stabilized total added mass coefficient Cm,total (inferred critical mass ratio m*_crit) =
approx -1.1 for m*=1.0, approx -1.12 for m*=2.4; m*_crit approx 1.1
- Excitation and added mass coefficients Cv and Cm per pipe =
Reported per UR for upstream and downstream pipes
assumptions (5)
- domain assumption The rigidly coupled twin-pipe system under FIV can be modeled as a single-degree-of-freedom cross-flow oscillator with total force F_up+F_down.
- domain assumption The added mass coefficient used to define natural frequency in water is Cm = 1 (potential-flow value for a single cylinder).
- domain assumption The time-delay compensation formula ce = (mp,up+mp,down) omega^2 dt from Ren et al. (2024) is valid for the twin-pipe VPF.
- ad hoc to paper The critical mass concept of Govardhan and Williamson (2002), developed for isolated cylinders, transfers to rigidly coupled tandem twin-pipes with the total Cm of both pipes.
- domain assumption The measured force on each pipe can be decomposed into velocity-proportional and acceleration-proportional components with constant coefficients Cv and Cm over a test segment.
Cite this review
Pith. "Pith review of Flow-induced vibration of twin-pipe model with varying mass and damping: A study using virtual physical framework." pith.science (2026). https://pith.science/paper/MWF2AX3O
@misc{pith2026250605649,
author = {Pith},
title = {Pith review of: Flow-induced vibration of twin-pipe model with varying mass and damping: A study using virtual physical framework},
year = {2026},
howpublished = {\url{https://pith.science/paper/MWF2AX3O}},
note = {Machine review of arXiv:2506.05649}
}
abstract
Flow-induced vibration (FIV) commonly occurs in rigidly coupled twin-pipe structures. However, the limited understanding of their FIV responses and hydrodynamic features presents a major challenge to the development of reliable engineering designs. To bridge this gap, the present study systematically investigates the FIV characteristics of a rigidly coupled twin-pipe model with elastic support using a virtual physical framework (VPF), which enables flexible control of structural parameters during physical testing. A distinctive feature of twin-pipe structures is the presence of in-line hydrodynamic interactions and torsional moments arising from the rigid coupling. The in-line interaction is primarily compressive and becomes more pronounced as the mass ratio increases. The torsional moment coefficient exhibits a rise-fall trend with increasing reduced velocity $U_R$ and stabilizes around 0.46 at low mass ratios. In addition, an "amplitude drop" phenomenon is observed at $U_R=6$, attributed to energy dissipation from the downstream pipe. The mass ratio significantly affects FIV amplitude, frequency, and hydrodynamic coefficients. As the mass ratio decreases, the synchronization region broadens and the hydrodynamic coefficients become more stable. At mass ratio of 1.0, a "resonance forever" behavior is observed. Damping primarily suppresses FIV amplitude, with minimal impact on dominant frequency and hydrodynamic coefficients. These findings provide valuable insights into twin-pipe FIV mechanisms and support a scientific basis for future structural design optimization.
Figures
Figures from the paper (8 more)
Reference graph
Works this paper leans on
-
[1]
author Alam [ M.M.] , author Moriya [ M.] , author Takai [ K.] , author Sakamoto [ H.] . title Fluctuating fluid forces acting on two circular cylinders in a tandem arrangement at a subcritical reynolds number . journal Journal of Wind Engineering and Industrial Aerodynamics year 2003 ; volume 91 ( number 1-2 ): pages 139--154
work page 2003
-
[2]
title Duhamel's principle for temporally inhomogeneous evolution equations in banach space
author Arosio [ A.] . title Duhamel's principle for temporally inhomogeneous evolution equations in banach space. journal NONLINEAR ANAL THEORY METHODS APPLIC year 1984 ; volume 8 ( number 9 ): pages 997--1010
work page 1984
-
[3]
title Effects of mass and damping ratios on viv of a circular cylinder
author Bahmani [ M.] , author Akbari [ M.] . title Effects of mass and damping ratios on viv of a circular cylinder . journal Ocean Engineering year 2010 ; volume 37 ( number 5-6 ): pages 511--519
work page 2010
-
[4]
author Deng [ S.] , author Ren [ H.] , author Xu [ Y.] , author Fu [ S.] , author Moan [ T.] , author Gao [ Z.] . title Experimental study of vortex-induced vibration of a twin-tube submerged floating tunnel segment model . journal Journal of Fluids and Structures year 2020 a ; volume 94 : pages 102908
work page 2020
-
[5]
author Deng [ S.] , author Ren [ H.] , author Xu [ Y.] , author Fu [ S.] , author Moan [ T.] , author Gao [ Z.] . title Experimental study on the drag forces on a twin-tube submerged floating tunnel segment model in current . journal Applied Ocean Research year 2020 b ; volume 104 : pages 102326
work page 2020
-
[6]
author Ehlers [ S.] , author Abdussamie [ N.] , author Branner [ K.] , author Fu [ S.] , author Hoogeland [ M.] , author Kolari [ K.] , author Lara [ P.] , author Michailides [ C.] , author Murayama [ H.] , author Rizzo [ C.] , et al. title Committee v. 2: Experimental methods . In: booktitle International Ship and Offshore Structures Congress . organizat...
work page 2022
-
[7]
title Vortex-induced vibration of a flexible pipe under oscillatory sheared flow
author Fu [ X.] , author Fu [ S.] , author Zhang [ M.] , author Ren [ H.] , author Zhao [ B.] , author Xu [ Y.] . title Vortex-induced vibration of a flexible pipe under oscillatory sheared flow . journal Physical Review Fluids year 2024 ; volume 9 ( number 1 ): pages 014604
work page 2024
-
[8]
title Modes of vortex formation and frequency response of a freely vibrating cylinder
author Govardhan [ R.] , author Williamson [ C.] . title Modes of vortex formation and frequency response of a freely vibrating cylinder . journal Journal of Fluid Mechanics year 2000 ; volume 420 : pages 85--130
work page 2000
Show all 33 references
-
[9]
title Resonance forever: existence of a critical mass and an infinite regime of resonance in vortex-induced vibration
author Govardhan [ R.] , author Williamson [ C.] . title Resonance forever: existence of a critical mass and an infinite regime of resonance in vortex-induced vibration . journal Journal of Fluid Mechanics year 2002 ; volume 473 : pages 147--166
2002
-
[10]
title Defining the ‘modified griffin plot’in vortex-induced vibration: revealing the effect of reynolds number using controlled damping
author Govardhan [ R.] , author Williamson [ C.] . title Defining the ‘modified griffin plot’in vortex-induced vibration: revealing the effect of reynolds number using controlled damping . journal Journal of fluid mechanics year 2006 ; volume 561 : pages 147--180
2006
-
[11]
title Forces on oscillating uniform and tapered cylinders in cross flow
author Hover [ F.] , author Techet [ A.] , author Triantafyllou [ M.] . title Forces on oscillating uniform and tapered cylinders in cross flow . journal Journal of Fluid Mechanics year 1998 ; volume 363 : pages 97--114
1998
-
[12]
title Flow around two elastically-mounted cylinders with different diameters in tandem and staggered configurations in the subcritical reynolds number regime
author Janocha [ M.J.] , author Ong [ M.C.] , author Nystr m [ P.R.] , author Tu [ Z.] , author Endal [ G.] , author Stokholm [ H.] . title Flow around two elastically-mounted cylinders with different diameters in tandem and staggered configurations in the subcritical reynolds...
2021
-
[13]
title Investigation of relative effects of mass and damping in vortex-induced vibration of a circular cylinder
author Khalak [ A.] , author Williamson [ C.H.] . title Investigation of relative effects of mass and damping in vortex-induced vibration of a circular cylinder . journal Journal of Wind Engineering and Industrial Aerodynamics year 1997 ; volume 69 : pages 341--350
1997
-
[14]
title Developing a cyber-physical fluid dynamics facility for fluid--structure interaction studies
author Mackowski [ A.W.] , author Williamson [ C.H.] . title Developing a cyber-physical fluid dynamics facility for fluid--structure interaction studies . journal Journal of Fluids and Structures year 2011 ; volume 27 ( number 5-6 ): pages 748--757
2011
-
[15]
title On the origin of wake-induced vibration in two tandem circular cylinders at low reynolds number
author Mysa [ R.C.] , author Kaboudian [ A.] , author Jaiman [ R.K.] . title On the origin of wake-induced vibration in two tandem circular cylinders at low reynolds number . journal Journal of Fluids and Structures year 2016 ; volume 61 : pages 76--98
2016
-
[16]
title Developing a virtual physical system for vortex-induced vibration studies of a bluff body
author Ren [ H.] , author Fu [ S.] , author Zhang [ M.] , author Xu [ Y.] , author Ren [ H.] . title Developing a virtual physical system for vortex-induced vibration studies of a bluff body . journal Journal of Ocean Engineering and Science year 2024
2024
-
[17]
title Experimental investigation on vortex induced vibration of a rigidly coupled twin-tube model
author Shen [ J.] , author Fu [ S.] , author Zhang [ M.] , author Niu [ Z.] , author Hua [ Y.] , author Xu [ Y.] , author Chu [ Y.] , author Bin [ S.] . title Experimental investigation on vortex induced vibration of a rigidly coupled twin-tube model . In: booktitle Internatio...
2024
-
[18]
title An investigation into the hydrodynamics of a flexible riser undergoing vortex-induced vibration
author Song [ L.] , author Fu [ S.] , author Cao [ J.] , author Ma [ L.] , author Wu [ J.] . title An investigation into the hydrodynamics of a flexible riser undergoing vortex-induced vibration . journal Journal of Fluids and Structures year 2016 ; volume 63 : pages 325--350
2016
-
[19]
title Drag coefficients of long flexible cylinders
author Vandiver [ J.K.] . title Drag coefficients of long flexible cylinders . In: booktitle Offshore technology conference . organization OTC ; year 1983 . p. pages OTC--4490
1983
-
[20]
title A brief review of recent results in vortex-induced vibrations
author Williamson [ C.] , author Govardhan [ R.] . title A brief review of recent results in vortex-induced vibrations . journal Journal of Wind engineering and industrial Aerodynamics year 2008 ; volume 96 ( number 6-7 ): pages 713--735
2008
-
[21]
title Vortex-induced vibrations
author Williamson [ C.H.] , author Govardhan [ R.] . title Vortex-induced vibrations . journal Annu Rev Fluid Mech year 2004 ; volume 36 ( number 1 ): pages 413--455
2004
-
[22]
title Wake interactions between two side-by-side circular cylinders with different sizes
author Zhang [ K.] , author Haque [ M.N.] . title Wake interactions between two side-by-side circular cylinders with different sizes . journal Physical Review Fluids year 2022 ; volume 7 ( number 6 ): pages 064703
2022
-
[23]
title Drag coefficients of double unequal-diameter flexible cylinders in tandem undergoing vortex/wake-induced vibrations
author Zhao [ B.] , author Zhang [ M.] , author Fu [ S.] , author Fu [ X.] , author Ren [ H.] , author Xu [ Y.] . title Drag coefficients of double unequal-diameter flexible cylinders in tandem undergoing vortex/wake-induced vibrations . journal Ocean Engineering year 2023 a ;...
2023
-
[24]
title Experimental investigation on vortex/wake-induced force of double unequal-diameter flexible cylinders in tandem
author Zhao [ B.] , author Zhang [ M.] , author Fu [ S.] , author Fu [ X.] , author Sun [ T.] , author Song [ B.] . title Experimental investigation on vortex/wake-induced force of double unequal-diameter flexible cylinders in tandem . journal Physics of Fluids year 2023 b ; v...
2023
-
[25]
title Flow induced vibration of two rigidly coupled circular cylinders in tandem and side-by-side arrangements at a low reynolds number of 150
author Zhao [ M.] . title Flow induced vibration of two rigidly coupled circular cylinders in tandem and side-by-side arrangements at a low reynolds number of 150 . journal Physics of Fluids year 2013 ; volume 25 ( number 12 )
2013
-
[26]
title Vortex-induced vibrations of two tandem rigidly coupled circular cylinders with streamwise, transverse, and rotational degrees of freedom
author Zhu [ H.] , author Zhao [ Y.] , author Qiu [ T.] , author Lin [ W.] , author Du [ X.] , author Dong [ H.] . title Vortex-induced vibrations of two tandem rigidly coupled circular cylinders with streamwise, transverse, and rotational degrees of freedom . journal Physics ...
2023
-
[27]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
-
[28]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
-
[29]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
-
[30]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
-
[31]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
-
[32]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
-
[33]
write newline
" write newline "" before.all 'output.state := FUNCTION n.dashify 't := "" t empty not t #1 #1 substring "-" = t #1 #2 substring "--" = not "--" * t #2 global.max substring 't := t #1 #1 substring "-" = "-" * t #2 global.max substring 't := while if t #1 #1 substring * t #2 gl...
Reviewed August 7, 2026 · model on record in the stance chip above.
Discussion (0). Sign in to comment.