Scipediacontent: Scipediacontent moved page Draft Content 405699540 to Larsen et al 2016a

2021-01-28T20:35:01Z

Scipediacontent moved page Draft Content 405699540 to Larsen et al 2016a

Scipediacontent: Created page with " == Abstract == Through complementary experimental and numerical efforts, the present paper aims to make a significant contribution to the overall understanding of backfillin..."

2021-01-28T20:34:56Z

Created page with " == Abstract == Through complementary experimental and numerical efforts, the present paper aims to make a significant contribution to the overall understanding of backfillin..."

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== Abstract ==

Through complementary experimental and numerical efforts, the present paper aims to make a significant contribution to the overall understanding of backfilling processes beneath submarine pipelines. For this purpose, we aim to simplify the experimental backfilling process to an elementary two-stage process: (1) initial scour induced by a pure current, followed by: (2) backfilling induced by pure waves. A steady current is introduced via a re-circulating pump, and is kept constant with a cross-sectional velocity of V = 0.48 m/s until an initial equilibrium scour depth, S0, is reached. Then, the current is stopped and waves (characterized by their Keulegan-Carpener number KC and Shields parameter θ)are introduced to initiate the backfilling process, which is maintained until a new equilibrium scour depth, Sf, is reached. The time at which waves are introduced will be denoted as t = 0. For the backfilling process both regular and irregular waves are used during the experiments. As a demonstration of the initiated two-stage (scour followed by backfilling) process, bed profiles based on video recordings from a case having KC = 9.7 and ϴ = 0.195,are depicted at selected stages in Figure 1. Figure 1(upper left) depicts the current-induced equilibrium scour hole in the near vicinity of the pipe at t = 0, with the profile approximated as the dashed red line. Similarly, Figure 1(upper right) depicts the new equilibrium scour profile (approximated as the full blue line) that has developed under wave-induced backfilling, corresponding to t = 60min. To ease comparison, the dashed red and full bluelines from these plots are additionally combined onto Figure 1 (bottom).The experimental campaign has additionally been complemented with similar numerical simulations (using regular waves), based on a fully-coupled hydrodynamicand morphodynamic CFD model (Jacobsen et al., 2014),extending previous pipeline scour-related applications ofFuhrman et al. (2014) and Larsen et al. (2016). Comparison of the numerical and experimental results demonstrate the ability of the CFD model to reasonably simulate the current-to-wave backfilling process, both interms of the achieved new wave induced equilibriumscour depths as well as the corresponding backfilling timescales. Figure 2 depicts a summary of both experimental and numerical backfilling time scale Tb versus Shields parameter θ. As can be seen, both experimental as well as numerical results match the regression equation:T<sub>b</sub>=0.3 θ-<sup>5/3 </sup>quite closely (solid line in Figure 2).

== Original document ==

The different versions of the original document can be found in:

* [https://backend.orbit.dtu.dk/ws/files/126135693/Bayraktaretal.pdf https://backend.orbit.dtu.dk/ws/files/126135693/Bayraktaretal.pdf]

* [https://api.elsevier.com/content/article/PII:S0378383916302022?httpAccept=text/xml https://api.elsevier.com/content/article/PII:S0378383916302022?httpAccept=text/xml],
: [https://api.elsevier.com/content/article/PII:S0378383916302022?httpAccept=text/plain https://api.elsevier.com/content/article/PII:S0378383916302022?httpAccept=text/plain],
: [http://dx.doi.org/10.1016/j.coastaleng.2016.08.010 http://dx.doi.org/10.1016/j.coastaleng.2016.08.010] under the license https://www.elsevier.com/tdm/userlicense/1.0/

* [https://orbit.dtu.dk/en/publications/672fdd56-b777-4221-9ee4-abf028e9df43 https://orbit.dtu.dk/en/publications/672fdd56-b777-4221-9ee4-abf028e9df43],
: [https://backend.orbit.dtu.dk/ws/files/127443016/1317.pdf https://backend.orbit.dtu.dk/ws/files/127443016/1317.pdf]

* [https://orbit.dtu.dk/en/publications/experimental-and-numerical-study-of-waveinduced-backfilling-beneath-submarine-pipelines(f88fc3a3-d2c4-4823-a413-7cb202520f79).html https://orbit.dtu.dk/en/publications/experimental-and-numerical-study-of-waveinduced-backfilling-beneath-submarine-pipelines(f88fc3a3-d2c4-4823-a413-7cb202520f79).html],
: [https://doi.org/10.1016/j.coastaleng.2016.08.010 https://doi.org/10.1016/j.coastaleng.2016.08.010],
: [https://backend.orbit.dtu.dk/ws/files/126135693/Bayraktaretal.pdf https://backend.orbit.dtu.dk/ws/files/126135693/Bayraktaretal.pdf]

* [https://www.sciencedirect.com/science/article/pii/S0378383916302022 https://www.sciencedirect.com/science/article/pii/S0378383916302022],
: [https://orbit.dtu.dk/files/126135693/Bayraktaretal.pdf https://orbit.dtu.dk/files/126135693/Bayraktaretal.pdf],
: [https://backend.orbit.dtu.dk/ws/files/127443016/1317.pdf https://backend.orbit.dtu.dk/ws/files/127443016/1317.pdf],
: [https://orbit.dtu.dk/en/publications/experimental-and-numerical-study-of-wave-induced-backfilling-bene https://orbit.dtu.dk/en/publications/experimental-and-numerical-study-of-wave-induced-backfilling-bene],
: [https://staging.orbit.dtic.dk/en/publications/experimental-and-numerical-study-of-wave-induced-backfilling-bene https://staging.orbit.dtic.dk/en/publications/experimental-and-numerical-study-of-wave-induced-backfilling-bene],
: [https://core.ac.uk/display/84001651 https://core.ac.uk/display/84001651],
: [https://academic.microsoft.com/#/detail/2519299358 https://academic.microsoft.com/#/detail/2519299358]

* [ ]

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Larsen et al 2016a - Revision history

Scipediacontent: Scipediacontent moved page Draft Content 405699540 to Larsen et al 2016a

Scipediacontent: Created page with " == Abstract == Through complementary experimental and numerical efforts, the present paper aims to make a significant contribution to the overall understanding of backfillin..."