• Honam Mathematical Journal
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• v.35 no.4
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• pp.775-791
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• 2013

The twisted torus knots and the primitive/Seifert knots both lie on a genus 2 Heegaard surface of $S^3$. In [5], J. Dean used the twisted torus knots to provide an abundance of examples of primitive/Seifert knots. Also he showed that not all twisted torus knots are primitive/Seifert knots. In this paper, we study the other inclusion. In other words, it shows that not all primitive/Seifert knots are twisted torus knot position. In fact, we give infinitely many primitive/Seifert knots that are not twisted torus knot position.

• Journal of the Korean Mathematical Society
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• v.44 no.4
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• pp.915-929
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• 2007

The main result of this paper is to construct the derivative twisted p-adic (h, q)-L-functions at s = 0. We obtain twisted version of Theorem 4 in [17]. We also obtain twisted (h, q)-extension of Proposition 1 in [3].

• Bulletin of the Korean Mathematical Society
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• v.52 no.2
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• pp.603-618
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• 2015

We derive three identities of symmetry in two variables and eight in three variables related to generalized twisted Bernoulli polynomials and generalized twisted power sums, both of which are twisted by unramified roots of unity. The case of ramified roots of unity was treated previously. The derivations of identities are based on the p-adic integral expression, with respect to a measure introduced by Koblitz, of the generating function for the generalized twisted Bernoulli polynomials and the quotient of p-adic integrals that can be expressed as the exponential generating function for the generalized twisted power sums.

• Journal of applied mathematics & informatics
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• v.39 no.3_4
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• pp.455-467
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• 2021

In this paper, we define twisted q-Euler polynomials of the second kind and explore some properties. We find generating function of twisted q-Euler polynomials of the second kind. Also, we investigate twisted q-Raabe's multiplication formula and (w, q)-alternating power sums of twisted q-Euler polynomials of the second kind. At the end, we define twisted q-Hurwitz's type Euler zeta function of the second kind.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.3
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• pp.715-722
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• 2014

Three twisted rudders fit for large container ships have been developed; 1) the Z-twisted rudder that is an asymmetry type taking into consideration incoming flow angles of the propeller slipstream, 2) the ZB-twisted rudder with a rudder bulb added onto the Z-twisted rudder, and 3) the ZB-F twisted rudder with a rudder fin attached to the ZB-twisted rudder. The twisted rudders have been designed computationally with the hydrodynamic characteristics in a self-propulsion condition in mind. The governing equation is the Navier-Stokes equations in an unsteady turbulent flow. The turbulence model applied is the Reynolds stress. The calculation was carried out in towing and self-propulsion conditions. The sliding mesh technique was employed to simulate the flow around the propeller. The speed performances of the ship with the twisted rudders were verified through model tests in a towing tank. The twisted versions showed greater performance driven by increased hull efficiency from less thrust deduction fraction and more effective wake fraction and decreased propeller rotating speed.

• Journal of applied mathematics & informatics
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• v.33 no.5_6
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• pp.649-656
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• 2015

In this paper we investigate some symmetric property of the twisted q-Euler zeta functions and twisted q-Euler polynomials.

• Journal of the Korean Mathematical Society
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• v.40 no.6
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• pp.963-975
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• 2003

The aim of this work is to construct twisted q-L-series which interpolate twisted q-generalized Bernoulli numbers. By using generating function of q-Bernoulli numbers, twisted q-Bernoulli numbers and polynomials are defined. Some properties of this polynomials and numbers are described. The numbers $L_{q}(1-n,\;X,\;{\xi})$ is also given explicitly.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.131-142
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• 2019

In this paper, a Wavy Twisted Rudder (WTR) is proposed to address the discontinuity of the twisted section and increase the stalling angle in comparison to a conventional full-spade Twisted Rudder (TR). The wave configuration was applied to a KRISO Container Ship (KCS) to confirm the characteristics of the rudder under the influence of the propeller wake. The resistance, self-propulsion performance, and rudder force at high angles of the wavy twisted rudder and twisted rudder were compared using Computational Fluid Dynamics (CFD). The numerical results were compared with the experimental results. The WTR differed from the TR in the degree of separation flow at large rudder angles. This was verified by visualizing the streamline around the rudder. The results confirmed the superiority of the WTR in terms of its delayed stall and high lift-drag ratio.

• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.3
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• pp.122-128
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• 2007

Heat transfer distributions and friction factors in square channels (3.0 ${\times}$ 3.0 cm) with twisted tape inserts and with twisted tape inserts plus interrupted ribs are respectively investigated. The rib height-to-channel hydraulic diameter ratio, $e/D_h$, is kept at 0.067 and test section length-to-hydraulic diameter ratio, $L/D_h$ is 30. The square ribs are arranged to follow the trace of the twisted tape and along the flow direction defined as axial interrupted ribs. The twisted tape is 0.1 mm thick carbon steel sheet with diameter of 2.8 cm, length of 90 cm, and 2.5 turns. Two heating conditions are investigated for test channels with twisted tape inserts and rib turbulators: (1) electric heat uniformly applied to four side walls of the square duct, and (2) electric heat uniformly applied to two opposite ribbed walls of the square channel. Results show that the twisted tape with interrupted ribs provides a higher overall heat transfer performance over the twisted tape with no ribs.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.169-177
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• 2018

Twisted rudder, twisted rudder with bulb, and twisted rudder with bulb and fin have been developed computationally for 3,000 TEU container ship through parametric study. The objective function is to minimize delivered power in model scale. Design variables are twisted angle, rudder bulb diameter and fin angle. The governing equation is Reynolds averaged Navier-Stokes equations in an unsteady turbulent flow and the Reynolds stress model applied for the turbulent closure. A double body model is used for the treatment of free-surface. The calculation was carried out in towing and self-propulsion conditions at design speed. The sliding mesh technique was employed to simulate the flow around the propeller. Form factor is obtained from the towing computation. Self-propulsion point is obtained from the self-propelled computations at two propeller rotating speeds. The delivered power due to the designed twisted rudder, twisted rudder with bulb, and twisted rudder with bulb and fin are reduced by 1.1%, 1.6%, and 2.0%, respectively.