commit 5ea1f8d33c5786f213a03c5a5bb5e304dcb36ea1
parent 9d4bec0f8c8b341da1203cb9344bf40f49abca50
Author: Ivan Gankevich <i.gankevich@spbu.ru>
Date: Fri, 13 Mar 2020 13:23:46 +0300
Introduction.
Diffstat:
| main.tex | | | 47 | ++++++++++++++++++++++++++++++++++++++++++++++- |
1 file changed, 46 insertions(+), 1 deletion(-)
diff --git a/main.tex b/main.tex
@@ -30,7 +30,7 @@
\email{TODO@student.spbu.ru},\\
\email{i.gankevich@spbu.ru},\\
\email{st016177@student.spbu.ru},\\
-\email{v.khramusin@spbu.ru},\\
+\email{v.khramushin@spbu.ru},\\
\email{st049350@student.spbu.ru}\\
\url{https://spbu.ru/}}
@@ -48,6 +48,51 @@ TODO
\end{abstract}
\section{Introduction}
+
+Ship motion simulation studies focus on interaction between the ship and ocean
+waves~--- a physical phenomena that gives the largest contribution to
+oscillatory motion~--- however, intelligent onboard systems require taking
+other forces into account. One of the basic functionality of such a system is
+determination of initial static ship stability parameters (roll angle, pitch
+angle and draught) from the recordings of various ship motion parameters, such
+as instantaneous roll, pitch and yaw angles, and their first and second
+instantaneous derivatives (e.g.~angular velocity and angular acceleration).
+During ship operation these initial static ship stability parameters deviate
+from the original values as a result of moving cargo between compartments,
+damaging the hull, compartment flooding etc. These effects are especially
+severe for fishing and military vessels, but can occur with any vessel
+operating in extreme conditions.
+
+Intelligent onboard system need large amount of synchronous recordings of ship
+motions parameters to operate, mainly angular displacement, velocity and
+acceleration and draught, but these parameters depend on the shape of the ship
+hull and obtaining them in model tests is complicated, let alone field tests.
+Field tests are too expensive to perform and do not allow to simulate
+particular phenomena such as compartment flooding. Model tests are too
+time-consuming for such a task and there is no reliable way to obtain all the
+derivatives for a particular parameter: sensors measure one particular
+derivative and all other derivatives have to calculated by numerical
+differentiation or integration, and integration has low accuracy for time
+series of measurements TODO. The simplest way to obtain those parameters is to
+simulate ship motion on the computer and save all the parameters in the file
+for future analysis.
+
+Arguably, the largest contribution to ship motion besides ocean waves is given
+by wind forces: air has lesser density than water, but air motion acts on the
+area of ship hull which is greater than underwater area due to ship
+superstructure. Steady wind may produce non-nought roll angle TODO, and thus
+have to be taken into account when determining initial static ship stability
+parameters.
+
+In this paper we investigate how wind velocity field can be simulated on the
+boundary and near the boundary of the ship hull. We derive a simple
+mathematical model for uniform translational motion of the air on the
+above-water boundary of the ship hull. Then we generalise this model to
+calculate wind velocity near the boundary still taking into account the shape
+of the above-water part of the ship hull. Finally, we measure the effect of
+wind velocity on the ship roll angle and carry out computational performance
+analysis of our programme.
+
\section{Methods}
\section{Results}
\section{Discussion}
