Numerical and Experimental Analysis of Total Hull Resistance on Floating Catamaran Pontoon for N219 Seaplanes based on Biomimetics Design with Clearance Configuration

Seaplanes are planes that can take off and land from the surface of water. Due to their ability to take off and land from the surface of water, seaplanes need a pair of pontoons in the form of a catamaran hull at the bottom of seaplanes so that the seaplanes can float above the surface of water. Research on the catamaran hull model was conducted to examine the effect of istiophorus platypterus design distance between hulls (clearance) variation on the total resistance of the catamaran hull model through experimental method and computational fluid dynamics (CFD) simulation method. There are three values of clearance (S/L) used in this research: 0.15, 0.2, and 0.25. The most optimal clearance configuration can be determined using a configuration which has the lowest total resistance. The results of experiments and simulations show that the distance between hull variations has a considerable effect on the total resistance of the catamaran hull model. The catamaran hull, which has the optimal clearance configuration, will cause the resulting wave interference and resistance to be small. The model was towed with Froude numbers ranging from 0.35 to 0.65. The results showed that hull separation made a difference in the total resistance coefficient on the same experiment configurations. The configurations with S/L 0.25 showed the least total resistance coefficient, whereas the configurations with the S/L 0.15 showed the highest total resistance coefficient. The simulations were conducted with the model with Froude numbers ranging from 0.35 to 0.65 using 700,000 cells in meshing and an error rate of 7.6% in convergence.

Catamaran; Computational fluid dynamics; Clearance; Resistance; Seaplanes

Float on seaplanes has a catamaran-type hull. There have been many studies that have attempted to create an optimal catamaran hull. Yang et al. (2002) examined the optimization of wave cancellations in multihull using computational fluid dynamics (CFD) tools. Efforts to reduce wave resistance in the sub-district were also investigated by Dan??man (2014) using the center bulb optimization concept Motion Sickness Incidence (MSI) in catamarans was also reviewed by Piscopo and Scamardella (2015). Research related to catamaran hulls will continue to grow, considering that 40% of ships worldwide use this type of hull design (Papanikolaou, 2005; Samuel et al., 2015).

    Design  optimization  on  a  float  can  be  seen  from  the  total  resistance,  that  will be described as follows. The total resistance is composed of viscous resistance related to the Reynolds number and wave resistance, which depends on the Froude number (Yanuar and Ibaddurahman, 2019). In the context of seaplane float, the optimization of catamaran designs is assessed based on the characteristics of the catamaran while in water, namely: (1) static load on water in the form of the width of each hull and total load on the floatplane; (2) float geometry; (3) position of the step float relative to the CG point (center of gravity) on the floatplane; (4) wing adjustment to the floatplane; (5) aerodynamic characteristics; and (6) the distance between the float centers. Good consideration of the characteristics of the float produces a design with stability in water, trim, spray, seaworthiness in the waves, aerodynamic shape, buoyancy, and ease in optimal manufacturing (Tomaszewski, 1950).

One of the optimization efforts that is often done in design engineering is biomimicry. This type of engineering is a process to create sustainable designs by mimicking the shape, mechanism, or evolution of various animals to the ecosystem they occupy (Pohlmann, 2016). In marine ecosystems, for example, the evolution of marine animals that have lasted more than 600 million years is believed to be the best and most efficient way of survival for these animals (Sani et al., 2013). With a variety of marine waters, these animals are able to survive, adapt to their environment, evolve, and survive extinction (Fish and Kocak, 2011). Sailfish (Istiophorus platypterus) is known as one of the fish that can go at high speed in the depths of the sea with an average speed of up to 30 km/h. Supported by body dimensions that can reduce barriers significantly, the swimming speed of the sailfish a type of fish is estimated to reach up to 126 km/h, one of the fastest when compared to other fish species (Svendsen et al., 2016). The aim and objective of this research are to create an optimal catamaran hull design which can be applied as a float on N219 aircraft by adapting the hydrodynamic characteristics of sailfish.

Float on seaplanes has a catamaran-type hull shape. Design optimization on a float can be seen from the total resistance. Sailfish (Istiophorus platypterus) have body dimensions that can significantly reduce barriers. The aim and objective of this research are to create a catamaran hull design as a float on N219 aircraft by adapting the hydrodynamic characteristics of sailfish. Tests using numerical methods are performed to determine the flow visualization of new hull designs' hydrodynamic characteristics. The adaptation of the hydrodynamic characteristics of sailfish on catamaran hulls is expected to optimize aircraft float design.

One mode of transportation that is currently being made in Indonesia is seaplanes. Seaplanes are specialized aircraft that can operate off the water and, thus, are completely independent of regular land-based airfields (Gudmundsson, 2013). Due to this ability, seaplanes can be operated to remote areas or islands in Indonesia as long as they have a large enough water surface area. Seaplanes can in general use wheels like planes for takeoff and landing on land and use pontoons to take off and land on the surface of water. The National Aeronautics and Space Agency and PT Dirgantara Indonesia are working together to develop a type of N219 aircraft that can be operated from land and the surface of water. The first stage in the development of amphibious N219 aircraft is the development of pontoons of the aircraft so that the aircraft can take off and land on the surface of water. The pontoons used in this N219 seaplane manuscript are in the form of a catamaran hull.

The application of catamaran hulls in the mode of transportation has developed rapidly today and is likely to continue to develop in the future (Moraes et al., 2007; Iqbal and Samuel, 2017; Yanuar et al., 2019). The rapid development of catamaran hulls as a mode of transportation is due to the catamaran hull dock area and the safety of its stability (Seif and Amini, 2004; Zouridakis, 2005).

 Multihull ships, including catamarans, have technical challenges, such as wave interference with various configurations when operated at high speeds, as stated by Yanuar et al. (2013). Catamaran hulls can have a small drag force by adjusting the proper hull distance ratio to create better efficiency. On multihull vessels, including catamarans, the problem of resistance is still widely discussed. Several studies on hull distance ratio have been investigated (Insel and Molland, 1992) as well as several experiments on catamaran resistance (Everest, 1968; Pien, 1976; Oving, 1985). This research aims to find the hull separation ratio (clearance) on a catamaran hull model for an N219 seaplane based on biomimetics to optimize the design using an experimental method and CFD simulation.

From the experimental testing and numerical testing and analysis carried out in this study, the following can be concluded: (1) Experimental testing of the floating pontoon configuration with the smallest total resistance coefficient (Ct) occurs at clearance (S/L) 0.25 with Froude Number (Fn) 0.75 of 0.00681, while the largest total drag coefficient (Ct) occurs at clearance (S/L) 0.15 with Froude Number (Fn) 0.40 with a value of 0.01337; (2) Numerical testing of the floating pontoon configuration with the smallest total drag coefficient (Ct) occurs at clearance (S/L) 0.25 with Froude Number (Fn) 0.75 of 0.00815, while the largest total drag coefficient (Ct) occurs at clearance (S/L) 0.15 with Froude Number (Fn) 0.40 with a value of 0.01133; (3) The results of numerical testing are carried out with validation with an error of 15.28% on the total resistance coefficient test compared to the experimental test results; (4) The biomimetics design is much preferable to that of a previous study done by Yanuar et al. (2019) because it uses a catamaran design rather than a pentamaran design to achieve the same total resistance at the same speed. 

    This research is funded by Program Hibah PUTI Proceedings under contract number NKB-1098/UN2.RST/HKP.05.00/2020.

Bustos, D.S.H., Alvarado, R.J.P., 2017. Numerical Hull Resistance Calculation of a Catamarán using Openfoam. Ciencia y tecnología de buques, Volume 11(21), pp. 29–39

Dan??man, D., 2014. Reduction of Demi-Hull Wave Interference Resistance in Fast Displacement Catamarans Utilizing an Optimized Centerbulb Concept. Ocean Engineering, Volume 91, pp. 227–234

Everest, J.T., 1968. Some Research on the Hydrodynamics of Catamarans and Multi-Hulled Vessels. In: North East Coast Institution of Engineers and Shipbuilders, N.n, Ulan Press, France, pp 1–20

Fish, F.E., Kocak, M.D., 2011. Biomimetics and Marine Technology: An Introduction. Marine Technology Society Journal, Volume 45(4), pp.  8–13

Gudmundsson, S., 2013. General Aviation Aircraft Design: Applied Methods and Procedures. 1^st Edition. London: Elsevier

Guo, B., Ghalambor, A., Duan, S., 2004. A Rigorous Approach to Estimating Permeability from Capillary Pressure Curves. Petroleum Science and Technology, Volume 22(3-4), pp. 319–335

Insel, M., Molland, A.F., 1992. An Investigation into the Resistance Components of High-Speed Displacement Catamarans. Trans RINA, Volume 134, pp. 1–20

Iqbal, M., Samuel., 2017. Traditional Catamaran Hull Form Configurations that Reduce Total Resistance. International Journal of Technology, Volume 8(1), pp. 85–93

ITTC, 2011. Recommended Procedures and Guideline: 7.5-02 -02-01. Resistance Test. Rev 03

Moraes, H.B., Vasconcellos, J.M., Almeida, P.M., 2007. Multiple Criteria Optimization Applied to High-Speed Catamaran Preliminary Design. Ocean Engineering, Volume 34(1), pp. 133–147

Moraes, H., Vasconcellos, J., Latorre, R., 2004. Wave Resistance for High-Speed Catamarans. Ocean Engineering, Volume 31(17-18), pp. 2253–2282

Oving, A.J., 1985. Resistance Prediction Method for Semi Planing Catamarans with Symmetrical Demi-hulls. Master’s Thesis, Graduate Program, Delft University of Technology, Mekelweg, Nedherland

Ozdemir, Y.H., Barlas, B., Yilmaz, T., Bayraktar, S., 2014. Numerical and Experimental Study of Turbulent Free Surface Flow for a Fast Ship Model. Brodogradnja, Volume 65(1), pp. 39–54

Papanikolaou, A., 2005. Review of Advanced Marine Vehicles Concepts. In: Proceedings of the 7^th Symposium on High-Speed Marine Vehicles (HSMV), Napoli, Italy, 21-23 September 2005

Pien, P.C., 1976. Catamaran Hull-Form Design. In: International Seminar on Wave Resistance, Society of Naval Architects of Japan (SNAJ), pp. 14–25

Piscopo, V., Scamardella, A., 2015. The Overall Motion Sickness Incidence Applied to Catamarans. International Journal of Naval Architecture and Ocean Engineering, Volume 7(4), pp. 655–669

Pohlmann, D.L., 2016. Review: Biomimicry-Innovations Inspired by Nature by Janine M. Benyus US-NY William Morrow. INSIGHT, Volume 19(3), pp. 78–78

Samuel., Iqbal, M., Utama, I.K.A.P., 2015. An Investigation into the Resistance Components of Converting a Traditional Monohull Fishing Vessel into Catamaran Form. International Journal of Technology, Volume 6(3), pp. 432–441

Sani, M.S.H.M., Muftah, F., Tan, C.S., 2013. Biomimicry Engineering: New Area of Transformation Inspired by the Nature. In: Business Engineering and Industrial Applications Colloquium (BEIAC), pp. 477–482

Seif, M.S., Amini, E., 2004. Performance Comparison between Planing Monohull and Catamaran at High Froude Numbers. Iranian Journal of Science & Technology, Volume 28, pp. 435–441

Souto-Iglesias, A., Fernandez-Gutierrez, D., Pierez-Rojas, L., 2012. Experimental Assessment of Interference Resistance for a Series 60 Catamaran in Free and Fixed Trim-Sinkage Conditions. Ocean Engineering, Volume 53, pp. 38–47

Svendsen, M.B.S., Domenici, P., Marras, S., Krause, J., Boswell, K.M., Rodriguez-Pinto, I., Wilson, A.D.M., Kurvers, R.H.J.M., Viblanc, P.E., Finger, J.S., Steffensen, J.F., 2016. Maximum Swimming Speeds of Sailfish and Three Other Large Marine Predatory Fish Species based on Muscle Contraction Time and Stride Length: A Myth Revisited. Biology Open, Volume 5(10), pp. 1–18 

Tomaszewski, K.M., 1950. Hydrodynamic Design of Seaplane Floats. Report Ministry of Supply, Aero Nautical Research Council, London, England

Yang, C., Lohner, R., Soto, O., 2002. Optimization of a Wave Cancellation Multihull Ship using CFD Tools. Journal of Hydrodynamics, Volume 14(1), pp. 1–8

Yanuar., Gunawan., Talahatu, M.A., Indrawati, R.T., Jamaluddin, A., 2013. Resistance Analysis of Unsymmetrical Trimaran Model with Outboard Side Hulls Configuration. Journal of Marine Science and Application, Volume 12(3), pp. 293–297

Yanuar., Ibaddurahman., 2019. An Investigation of the Pentamaran Resistance Characteristic with Variance in Hull Combination and Configuration. Energy Procedia, Volume 156, pp. 469–474

Yanuar., Ibadurrahman., Putri, S.A.A., 2019. Resistance Characteristics of Submerged Projectile with Bow Variation based on Hull Envelope Equation using Steady RANS Simulation. International Journal of Technology, Volume 10(4), pp. 677–688

Zaghi, S., Broglia, R., Di Mascio, A., 2011. Analysis of the Interference Effects for High-Speed Catamarans by Model Tests and Numerical Simulations. Ocean Engineering, Volume 38(17-18), pp. 2110–2122

Zouridakis, F., 2005. A Preliminary Design Tool for Resistance and Powering Prediction of Catamaran Vessels. Master’s Thesis, Graduate Program, Massachusetts Institute of Technology, Cambridge, USA