Fin Shape Research Articles

Hydrodynamic effects of the caudal fin shape of fish in carangiform undulatory swimming

As an important structure for generating thrust, the shapes of fish tails have adaptively evolved to achieve great swimming performance through natural selection over hundreds of millions of years. The particular optimal tail shape of fish is not universal for all situations but significantly varies with other factors, such as undulatory kinematics. In this study, using a sharp-interface immersed boundary method with a self-propelled model, we investigated the hydrodynamic performance of swimmers that equipped with three different caudal fins in a common undulatory mode, carangiform locomotion, to determine the optimal shape. The three caudal fins tested are as follows: a round fin emulating that of snakehead fish ( channidae), an indented fin emulating that of saithe ( Pollachius virens), and a lunate fin emulating that of tuna ( Thunnus thynnus). At the regular undulating amplitude A = 0.1 L at the tail tip (L is the body length), the swimmer with the indented tail achieves the highest speed U = 1.45 L/s with a relatively high quasi-propulsive efficiency of η q = 0.324; at a higher undulating amplitude A = 0.15 L, the indented tail swimmer achieves slightly lower speed than the lunate fin swimmer, who has the highest speed (2.06 L/s vs. 2.07 L/s), but the efficiency of the former is higher than that of the latter. Therefore, the indented fin is believed to perform the best among the three fins tested regarding carangiform undulatory swimming. This finding is consistent with observations made on fish in nature, for example, carangiform swimming fish that have been evolving for hundreds of millions of years have a caudal fin similar to the indented caudal fin in the current study.

Optimization of Fin with Rectangular and Triangular Shapes by Levenberg – Marquardt Method

The article proposes using the Levenberg – Marquardt (L – M) method to optimize the fin with the longitudinal profile. The objective in optimizing the fin shape: The fin volume achieved the minimum value, with the optimization variables being the fin's width and length. The research performed two problems about optimal design the fin with the straight profile for triangular and rectangular shapes, obtained a tiny relative error compared to the results of the published studies. Specifically, the problem with the triangular-shaped fin, the relative error of the minimum volume compared to the two published is 0.022% & 0.092%; and the problem with the rectangular-shaped fin, the relative error is 0.68% & approximately 0%, respectively.

Thermal and Flow Analysis of Different Shaped Pin Fins for Improved Heat Transfer Rate

In this paper, a micro pin fin heat sink is numerically investigated with four fins geometries (circular, elliptical, square, and drop shape) at two types of arrangement styles, inline and staggered arrangement. The hydrodynamic and thermal characteristics of different fin geometries and two arrangement styles have been compared under the exact value of Reynolds number and constant wall temperature thermal boundary conditions. The Reynolds number was sweeping in the range of (400-2800) to ensure the fluid flow velocity impact in the pin fin performance. The results obtained indicate that a longitude pin fin dropped with increasing Reynolds number at a distributed temperature. Also, the circler Pin fin reaches the lowest temperature comparison to the rest of the three-pin fin types. Generally, according to the extracted, Nusselt number for different geometries increased versus increasing the Reynolds number. Observe that the elliptical fin shape yields the highest Nusselt number at all Reynolds numbers. Moreover, the elliptical pin fin ejects the highest heat transfer rate, which indicates the pin fin performance. Furthermore, skin friction has a significant function with variation in Reynolds number.

Investigation of Tip Temperature of a Ring Fashioned Fin for CI Engine Using Ansys Modeling

Abstract: As the name imply prolonged surfaces to extract most amount of heat via out the surfaces. There are such a lot of researcher check out the heat transfer from the C I engine by using the use of fins, however nobody can calculate the top temperature of fin and to formulate the result by way of using Finite Element approach. It's far very vital to transfer warmness from the C I engine .The warmth transfer coefficient may be decided the usage of superior FEA codes which include fluid mechanics .Those simplified terms constitute a aggregate of several elements ,which include powerful floor vicinity ,lateral fin conduction ,boundary layer formation and cloth conductivity. It's miles very difficult to modeled a hoop form fin .Each pin should be individually discredited ,increasing the modeling time significantly .On this studies we have to used simulation application will be advanced for predicting and optimizing thermal performance of different sorts of fin component like round fin, axial fin and we compare ring form fin with triangular profile .The end result of the ring form fin can be additionally in comparison with the ones axial fins and ring shape fin with triangular profile the use of finite detail evaluation software advanced on Ansys software. Apart from this we additionally look into the temperature size and thermal pressure distribution. Keywords: Geometric modeling, thermal stress distribution, triangular profile,

Abnormal trend in hot carrier degradation with fin profile in short channel FinFET devices at 14 nm node

This study investigates the impact of fin profiles under hot carrier stress, which defines different base widths: wide-base samples with the smallest slope, medium-base samples, and narrow-base samples with a larger slope. The performance of the narrow samples is better than the medium samples, regardless of transconductance, on-state current, subthreshold swing or drain-induced barrier lowering, demonstrating that the narrow profile samples’ mobility and gate control are better. In long channel devices, the trend of hot carrier degradation (HCD) is in agreement with previous references, and is dependent on the transverse electric field and the fin shapes. However, this trend does not exist for short-channel devices. Positive bias stress and technology computer aided design simulation are applied for investigation and to clarify the reasons for this abnormal HCD trend. Finally, by fitting the multiple vibrational excitation (MVE) mechanism, the slope of the trend lines in the short channel devices are found to indeed match the bending mode. In other words, the disappearance of the general trend between the HCD and fin profiles is caused by the change in the mechanism in the short-channel device. Because the MVE mechanism is independent from the electric field, the narrow profile fin shape more effectively promotes gate control and better performance without affecting the reliability in short channel devices. These results can provide a clear direction for fin shape designers in the future.

Study on thermal performance of a new optimized snowflake longitudinal fin in vertical latent heat storage

Taking the casing phase change heat storage unit filled with RT55 as the research object. According to the low thermal conductivity of phase change materials, we propose a Phase Change Material (PCM) sleeve with snowflake longitudinal fin structure to improve the melting performance of vertical latent heat storage system (LHTES), and the phase change heat transfer process is simulated by numerical simulation. We studied the enhanced heat transfer characteristics of the snowflake-shaped fin structure to the casing PCM unit, and compared with the ordinary rectangular longitudinal fin and the improved snowflake-shaped longitudinal fin. The results show that the combined mechanism of snowflake finned tube structure and local heat transfer of phase change materials can significantly shorten the charging time, which is 45.59% lower than that of traditional fin melting time. Reasonable changes in fin length, width, shape and angle structure can shorten the charging time, but reduce the heat storage. We analyzed the thermal performance of the heat storage system by taking the charging time, heat storage capacity and average heat flux as evaluation indexes, and discussed the effects of flow temperature in the tube, fin material and longitudinal fin shape on the melting performance of the system.

Two new species of the butterflyfish genus Roa (Perciformes: Chaetodontidae).

Two new species of Roa (Chaetodontidae) are described. Roa semilunaris sp. nov., based on six specimens from the Mascarene Ridge (south-western Indian Ocean), is most similar to Roa jayakari (Norman, 1939), distributed in the Red Sea and the northern Indian Ocean, in having scales on the upper jaw, interrupted pale lines within the second dark body band, and similar coloration and shape of the pelvic fin. However, the former is readily distinguished from R. jayakari by a wider whitish interspace between the second and third black bands [width of interspace at lateral line level 15.9%-18.5% of standard length (SL) in R. semilunaris sp. nov. (vs. 5.1%-8.5% of SL in R. jayakari)], with 9 or 10 pored lateral-line scales in the interspace (vs. 3-5); an oval or semicircular ocellated blotch on the soft-rayed portion of the dorsal fin (vs. a circular blotch); the head higher and longer [head length 35.0%-36.7% of SL (vs. 40.8%-44.1% of SL), head height 48.1%-50.5% of SL (vs. 52.0%-56.9% of SL)], and postorbital length 14.0%-15.1% of SL (vs. 17.0%-20.5% of SL). Roa uejoi sp. nov., based on three specimens from Guam (Mariana Islands), is most similar to Roa excelsa (Jordan, 1921) (now restricted to the Hawaiian Islands and Johnston Island), but is distinguished from the latter by having a circular dorsal-fin ocellated spot (vs. spot distinctly oval in the latter) and a much more elongate, filamentous first pelvic-fin soft ray, of length 119.0%-123.4% of 2nd ray (vs. not obviously filamentous, 104.9%-105.8%). A key to the eight valid species of Roa is provided.

Scyliorhinus hachijoensis, a new species of catshark from the Izu Islands, Japan (Carcharhiniformes: Scyliorhinidae).

A new species of catshark genus Scyliorhinus, S. hachijoensis sp. nov., is described for the islands of Mikurajima, Hachijojima, and Torishima in southeastern Japan. Scyliorhinus hachijoensis has clasper hooks, which is a common feature in males of the most closely related species (S. torazame), but is distinguished by its coloration (presence of dark spots), the height of its anal fin (higher than the caudal peduncle), and the shape of pectoral and pelvic fins, and dermal denticles. Molecular data also corroborates the new species as a distinct and monophyletic taxon by nucleotide sequence analysis of three mitochondrial DNA regions.

THE BEHAVIOR OF HEAT SINK-IMPINGEMENT COOLING WITH FLAT PLATE AND ARCED FINS MODELS

In this paper, a statistical analysis was applied to the numerical predictions of temperature distribution for the heat sinks. There are two types of heat sink with an array of impingement. The first type is a flat plate heat sink, and the second type is arcs-fins heat sinks. The second type category considers five models (A, B, C, D, and E). The shapes of fins were changed, but the thickness, distance between fins, and radius were held fixed for comparing and analyzing them depending upon the improvement of the fin geometry of heat sink. The heat sinks of the two types are subjected to multi impinging flow at different Reynolds numbers (7000-11000). Thermodynamic and hydraulic results were collected. The best model was calculated through a statistical analysis. The efficiency of an arcs-fin heat sink was superior to that of the flat plate heat sink. The findings of Model D were more appropriate than those of the other models. The concave arc near the heat sink's exit (model D) created better effect than the convex arc(model E), despite the fact that the (model D) shape fins being identical to (model E) shape fins (only rotated 180° at the same location). However, Descriptive Statistics manifested that in all situations, the mean temperature for (model D) is better than (model E). The results of comparison between the flat plate heat sink and models (D and E) evinced that the average heat sink temperaturein the suggested design reduced via 12%, 8%, while the (model E) decreased by 12%, 7% for Re (7000, 9000), respectively. In addition, the two models maintained the same percentage of (8% and 7%) improvement at Re (11000). The correlation coefficient between the flat plate and the arcs-fins heat sink for model B has the highest value (0.809), while model A has the lowest value of correlation (0.673).

Pool boiling simulation of two nanofluids at multi concentrations in enclosure with different shapes of fins

The boiling process is one of the important physical phenomena that is based mainly on the phase transformation of matter. As the importance of boiling has become great with the development of scientific physics in the present time due to the large number of its uses and benefit from it in physical processes. Where it became necessary to study and improve boiling in fluids and use nanomaterials to improve this boiling. Where in our research, the boiling of water at a temperature of 100 degrees Celsius was studied with the use of nanomaterials (CuO, Al2O3) and in different concentrations to understand their effect on the boiling process. With the addition of different shapes of fins that help to increase the surface area to add heat. Three shapes of rectangular, circle and triangle fins are used, which are the main shapes of the fins. The results show that with the increase in the concentrations of nanomaterials, the boiling process increases velocity of vapor and affects pressure and velocity of flow. The best shapes that give more area for the temperature and thus increase the boiling process and velocity compared to other cases that have been verified.

Study of Offshore Patrol Vessel Models for Seakeeping and Maneuvering Improvement using Anti-Rolling Fins

Offshore patrol vessel models using anti-rolling fins with variations of fin angle and shape are investigated in this study to improve the seakeeping and maneuvering performances, especially in the combat operation of the vessel. This study focused on the determination of the effect of adding fins to the seakeeping and maneuvering performances by optimizing fin angle and shape fitted on the ship hull. The 3D ship model with three variations of fin’s shape and four variations of the fin angle was analyzed using a numerical method of computational fluid dynamic (CFD) software. Result showed that fins type NAIAD 525, has the smallest average roll response occurs at 55 deg fin with motion amplitude 5.4E-05 deg. At the same fin angle, the average pitch amplitude reaches the smallest of 2.7E-03 deg. For PRAXIS type, the smallest average roll response occurs at 60 deg fin with motion amplitude 4.7E-05 deg. But for average pitch amplitude, the lowest value occurs at 45 deg of 2.7E-03 deg. And WESMAR type, the smallest average roll response occurs at 45 deg fin with motion amplitude 3.9E-05 deg. At the same fin angle, the average pitch amplitude reaches the smallest of 2.7E-03 deg. Turning maneuvers parameter of the vessel are comply with the IMO standard. The highest value of Tactical Diameter, which is 4.91 L, occurs in condition of no environmental disturbance, while the highest value of Advance occurs in wind disturbance condition with a value of 4.29 L.

Numerical investigation of modified fin shapes for the improved heat transfer

An examination of fin surfaces with various shapes was performed in this work to determine the most efficient heat transfer rate. Models, investigations, and studies have been conducted on the geometry of fin surfaces, namely normal fins with rectangular cross section (R-Fin), fins with multiple steps (S-Fin), and multiple step fins with dimples (D-Fin). Fin surfaces with higher surface area have improved heat transmission, as determined by conceptual and numerical investigation. According to numerical data, dimpled fins improve the surface region and heat transmission of the fins. The dimples had been constructed with changing diameters to fit the fins, which are 5 mm, 4 mm, and 3 mm in diameter, and have been evaluated using a static computational approach. The purpose of this study is to demonstrate the construction, evaluation, and outcome of several fin shapes with constant input boundary conditions. The spherical grooves with various diameters were found to be more successful than the other fins, and creating notches increased heat transmission far more than augmenting the size of the stepped fin's depression.

Numerical Investigation of Curved Shape Fins Height Effect on Flow Characteristics in Open Microchannel Heat Sink

Numerical Investigation of Curved Shape Fins Height Effect on Flow Characteristics in Open Microchannel Heat Sink

Influence of longitudinal fin arrangement on the melting and solidification inside the triplex tube latent heat thermal storage system

A two-dimensional melting/solidification model of Phase Change Material (PCM) is developed. The present research has studied the novel PCM based Triplex Tube Latent Heat Storage System (TTLHSS). The primary target of this research is to establish the effect of longitudinal fins on the performance of both melting and solidification rate of PCM. Initially, melting and solidification enhancement with four longitudinal fins are studied, and 60% and 46.15% reduction are observed in melting and solidification time. Then, the arrangement of fins inside TTLHSS is studied, and it is found that TTLHSS with three fins in the bottom portion can be more effective for melting enhancement. However, three fins in the bottom portion are not found beneficial for solidification enhancement. Then, instead of straight fins, l-shaped longitudinal fins are studied and found almost similar enhancement in melting as straight fins. At the same time, a 2–5% reduction in solidification time is observed with l-shaped fins. For further improvement, a greater number of fins with small lengths are examined. The fin volume remains the same in this case of eight fins and found good improvement in the melting and solidification processes. In short, three different parameters, fin arrangement, fin shape, and a number of fins are studied in current research. The case with a greater number of fins with reduced length is found maximum effective. The arrangement with eight fins (in which bottom fin length is increased with compensation of reduced side fin length) is found most effective with a 60.77% reduction in combined melting-solidification duration.

Synergistic effects of nano-enhanced phase change material (NePCM) and fin shape on heat storage performance of a finned shell-and-tube unit: An experimental study

Adding a fin or using a nano-enhanced phase change material (NePCM) can both improve the performance of shell-and-tube thermal energy storage (TES) units, but the combination of them may not be simple to achieve synergistic effect. In this paper, an experimental study was conducted to reveal the combined effects of fin shape and nano-additive loading on the heat storage performance of a finned shell-and-tube TES unit filled with NePCM, with nine cross-portfolio experimental configurations, i.e., three loadings of the nano-additive, graphene nanoplatelets (GNP) in this work, and three fin shapes including annular, helical and longitudinal fins. It was shown that the changes of GNP loading and fin shape could have either enhancement or deterioration effect on the various mechanisms of heat transfer during melting, such as conduction, convection, and close-contact melting mode, and that their combined effects on the heat transfer and heat storage rates of the TES unit are very complicated. The fin with a given shape should be combined with a suitable GNP loading to achieve synergistic effect for different application scenarios. For example, in pursuit of higher heat transfer rate (fast charging and discharging), the configuration of a certain GNP loading combined with the annular fin can be adopted. Considering the manufacturing cost, the annular fin with a gap between the fin and the shell wall can also be used to achieve the same heat transfer enhancement effect as that of the helical fin. In case of the longitudinal fin, the GNP loading has a great negative impact on the overall melting rate and the instantaneous heat storage rate, so it should be used in combination with pure PCM without adding any nano-additives.

Novel battery thermal management system with different shapes of pin fins

Battery thermal management systems (BTMS) with favorable working performance are essential for lithium-ion battery inside the electrical vehicles. In this research, a novel BTMS is proposed by introducing vertically and horizontally arranged square pin fins (SPFs), circular pin fins (CPFs), and ellipse pin fins (EPFs) into the cold plate. The overall cooling performance (efficiency index: EI) of the proposed BTMS is evaluated numerically, considering both heat transfer and pressure loss. It is found that BTMS with SPFs always achieve the best cooling performance but is penalized with a higher pressure loss. EPFs-arranged BTMS can achieve the lowest pressure loss due to the excellent streamlined structure, but its cooling performance is also the lowest among these three different pin fin shapes. Considering both heat transfer and pressure loss, CPFs can be the best choice for BTMS when pin fins are vertically arranged, due to the favorable cooling performance and acceptable pressure loss caused by CPFs. However, the pressure loss is larger for all horizontally arranged pin fins. Considering both heat transfer and friction factor, SPFs are recommended for BTMS because of the greater enhancement of heat transfer.

Numerical investigations of thermal performance enhancement in phase change energy storage system effective for solar adsorption cooling systems

Solar cooling systems requires an uninterrupted heat input for their continued operation. Thermal energy storage systems using phase change material (PCM) has the ability to deliver heat near isothermally and are effective for solar cooling applications. But these high energy dense storage systems exhibits poor thermal performance due to the low thermal conductivity of PCMs and are bulky. The main objective of this study is to design a phase change energy storage system (PCES) unit with different fin configurations, and to select a proper PCM for solar adsorption cooling systems (SAC). It projects the Preference Selection Index (PSI) method as the effective way to select the PCMs, and the result suggests the commercial PCM SavE-HS89 as a potential candidate among the different materials considered. This study also numerically investigates the thermal performance of different fins shapes, namely, positively tapered, negatively tapered and straight fins; among these the negatively tapered fins are found to be capable of compensating the slow melting process at the bottom region of the storage unit. It has been found that the negatively tapered fin improves the thermal performance of the PCES unit by reducing the melting time by up to 13% and 36% in comparison with the conventional straight fin and positively tapered fin, respectively. A case study of actual plant data of a SAC with different fin shapes shows that the storage system with the desirable configuration can save up to 46% of heat storage cost as compared to PCES without fin.

Design and Realization of Labriform Mode Swimming Robot Based on Concave Pectoral Fins

A Swimming performance underlies the biomechanical properties and functional morphology of fish fins. In this article, design and realization of a swimming robot propelled by a pair of pectoral fin is implemented. The suggested shape of the pectoral fins is concave; this type of fin provides a simple approach in generating effective hydrodynamic thrust force through only one degree of freedom (1-DOF). Next, we show the effect of varying fin oscillation speed in two phases, the first phase is the power stroke one, where the fins start to push toward the backward of the body, and the recovery phase, where the fins return toward the frontal part of the body. The detailed steps of the robot design are presented and the thrust force exerted by pectoral fins has been evaluated. The robot is consisting of a rigid-body with an elliptical cross-sectional area, which helps in minimizing the water resistance during the thrusting process. Since pectoral fins provide a vital role in the propulsion mechanism of Labridae fish, the proposed model is driven by a pair of concave-shaped fin to simulate labriform mode swimming mechanism. For motion control, we have suggested to use PID controller in order to improve the system performance. The kinematic and dynamic model of a swimming robot has been derived based on Newton-Euler equations, while an evaluation of the total hydrodynamic forces that are exerted on the swimming robot's body is studied via the computational fluid dynamics (CFD) method. The proposed design has been validated theoretically via Solidworks{\textregistered} platform and examined experimentally. The results of the simulation and practical experiments showed the validity and agility of Labriform swimming robot.

Effects of pin fins and vortex generators on thermal performance in a microchannel with Al2O3 nanofluids

This paper performs a comparative analysis to obtain the optimal cross-section shape and parameters of both pin fins and vortex generators. A novel combined structure with pin fins and vortex generators is proposed to enhance thermal performance of an integrated microchannel heat sink. Effects of nanoparticle diameter and volume fraction are investigated using Al2O3 nanofluid and DI-water as working fluid. Pin fins and vortex generators cause enhancements of flow disturbance and heat transfer on microchannel heat sinks. Results indicate that oval pin fins have better improvements of thermal/hydraulic performance compared to round and diamond pin fins. The oval pin fin with 0.4 mm spacing and 0.1 mm height presents the highest overall performance factor in the Reynolds number range of 340–640. Presence of vortices intensifies the mixing of the hot fluid near bottom surface and cold fluid near top surface. The optimal vortex generator with length of 0.08 mm and height of 0.06 mm provides a 30% increase in overall performance factor compared to the rectangular microchannel at Reynolds number of 340. Mechanism of heat transfer enhancement is analyzed by investigating flow velocity, temperature distribution and field synergy angle distribution in microchannels. Based on the field synergy principle, it is found that a small and uniformly distributed synergy angle is achieved in the integrated microchannel. According to comparisons of the overall performance factor and total thermal resistance, the optimal nanoparticle diameter and Al2O3 volume fraction of nanofluids are 20 nm and 4%, respectively.

Effect of copper foam fin (CFF) shapes on thermal performance improvement of the latent heat storage units

To overcome the poor thermal change of Phase Change Material (PCM), Copper Foam Fin (CFF) was innovatively utilized to enhance the PCM heat transfer capability and improve the thermal performance of vertical shell-and-tube latent heat storage units (LHSUs). Three CFF shapes, including annular CFF (ACFF), longitudinal CFF (LCFF) and compound CFF (CCFF), were designed with the same filling ratio of 30%. A contrastive experiment with three flow rates was conducted to evaluate the heat transfer capacity of LHSUs integrated with three CFF shapes. Experimental results showed the CFF shape had the large effects on the thermal performance of LHSU and that ACFF showed the most excellent thermal performance. Compared with LCFF and CCFF, adding ACFF could increase the melting rates by 14.1% and 3.9%, the solidification rates by 10.1% and 2.7%, and the thermal efficiency by 21.9% and 42.0%, respectively. And ACFF and CCFF units showed better performance in the liquid interface distribution and the temperature uniformity. Moreover, the volume flow rate had the small influence on the temperature response rate, but could improve the thermal efficiency significantly.