Selection of Publications
A Decision Support System For Energy Efficient Propulsion
Authors: Insel, M., Saydam, A.Z., Gokcay, S. (2017)
Published on: Trends and Challenges in Maritime Energy Management, Springer, ISBN:978-3-319-74576-3
Energy efficiency measures for cargo ships can be categorized into design and operation. Most of the design measures are based on hull form optimization, propulsion system selection and speed optimization. Operational measures are mainly based on selecting the optimized speed, trim, propeller pitch and rpm for energy efficiency. These measures should be applied on board according to the loading conditions and weather conditions, such as
wave height, period and direction, wind speed and direction.
CFD based vortex generator design and full-scale testing for wake non-uniformity reduction
Authors: Insel, M., Saydam, A.Z., Gokcay, S. (2018)
Published on: Ocean Engineering, (vol 153, 282-296)
Propeller-induced vibration on ships may originate from separation and wake non-uniformity and can be dealt with stern form redesign, wake adapted propeller design or wake modification devices such as fins, ducts or vortex generators. For an existing ship, the retrofit options are limited and vortex generators are the most cost efficient measure with quick and easy application. However, selection of the design parameters such as size, location and angle of attack relative to the flow are still not straightforward and can be very costly to be evaluated by model tests or full scale investigations. RANS based CFD methods can be used effectively to select these parameters. Current research presents a methodology through a full-scale test case consisting of initial numerical flow calculations and full scale testing, CFD calculations, final numerical flow calculations and full scale testing which shows significant improvements
EVALUATION OF WIND LOADS ON SHIPS BY CFD
Authors: Saydam, A.Z., Taylan, M. (2018)
Published on: Ocean Engineering, (vol 158, 54-63)
Effect of wind loads on marine structures and ships has to be considered during design. Static and dynamic effects of wind forces and moments are incorporated into the rules and regulations of governing authorities by various means. The weather criterion of IMO, part of the mandatory requirements of 2008 IS Code, considers the effect of wind and waves on stability of ships and has been in use for a long time. The criterion is simply based on static heel angle due to pre-defined wind pressure and moment balance concept with respective roll motion. There has been a lot of criticism about the assumptions and therefore validity of the criterion especially for the standard wind pressure of 504 Pa and linear distribution of heeling arms curve irrespective of heel angles. This paper deals with these questionable issues of the weather criterion. CFD analyses have been conducted on several different type of vessels in order to predict the wind forces. The results are then compared with those mandated by various criteria.