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Добірка наукової літератури з теми "Simulations rotor"

Автор: Grafiati

Опубліковано: 30 листопада 2024

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Статті в журналах з теми "Simulations rotor"

Fu, Ping, Hong Lei Zhang, and Chuan Sheng Wang. "Finite-Element Analysis of Rotor in the Rubber Continuous Plasticator." Key Engineering Materials 561 (July 2013): 174–77. http://dx.doi.org/10.4028/www.scientific.net/kem.561.174.

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The three-dimensional flow fields produced by the modular dual-rotor of rubber continuous plasticator were numerically simulated and analyzed by using ADINA, the FEM simulation software. So the velocity field distribution of each rotor element was shown by the simulations. Through the analysis, the double rotors rotated inward had high efficiency of pumping and plasticization. The rubber compound was subjected to the strong shearing action; squeezing action and stretch effect in the rubber plasticate process. The simulation calculation had great significance for the rotor optimizing design.

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Pacholczyk, Michał, and Dariusz Karkosiński. "Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine." Energies 13, no. 15 (July 29, 2020): 3880. http://dx.doi.org/10.3390/en13153880.

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A small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performance has been investigated numerically. Results of a parametric study have been presented in this paper. As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected. Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT). Simulations were carried out with Computational Fluids Dynamics (CFD) solver and a Large Eddy Scale approach to model turbulences. An Actuator Line Model has been chosen to represent rotors in the computational domain. Summing up the results of simulation tests, it can be stated that when constructing a CRWT turbine, rotors should be placed at a distance of at least 0.5 D (where D is rotor outer diameter) or more. One can then expect a noticeable power increase compared to a single rotor turbine. Placing the second rotor closer than 0.5 D guarantees a significant increase in power, but in such configurations, dynamic interactions between the rotors are visible, resulting in fluctuations in torque and power. Dynamic interactions between rotor blades above 0.5 D are invisible.

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Huang, Yong Yu, Qiu Yun Mo, Xu Zhang, and Zu Peng Zhou. "Numerical Simulations of Spherical Vertical-Axis Wind Rotor." Applied Mechanics and Materials 291-294 (February 2013): 456–60. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.456.

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In this paper, the effects of the shape of three types of the blade on power coefficient of Savonius rotors are studied by simulating the model using numerical simulation under the same conditions. For this purpose, three spherical rotors with different configurations but identical number of stages and blades, aspect ratio and overlap keeping the identical projected area of each rotor are constructed. The geometries of blade of the three rotors are a plane, a semi-circle and a quarter of sphere. The building data are calculated on the basis of the nominal wind velocity V= 10m/s and the speed ratio λ= 0.3 with an industrial flow simulation code (ANSYS-Fluent). The result shows that the rotor with semicircular blades has a higher value of power coefficient in comparison with other rotors.

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Mao, Xiaochen, and Bo Liu. "Numerical investigation of tip clearance size effect on the performance and tip leakage flow in a dual-stage counter-rotating axial compressor." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 3 (February 15, 2017): 474–84. http://dx.doi.org/10.1177/0954410016638878.

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Based on a validation of the numerical methods with an experiment, numerical simulations are carried out to study the effect of tip clearance size on the performance and tip leakage flow in a dual-stage counter-rotating axial compressor. The predicted results showed that the variation of the tip clearance size in rotor2 has a more significant impact on the overall performance and stall margin of the compressor. In addition, the impact of the tip clearance size effect is mainly on the rotor with the tip clearance size variation. The variation of the tip clearance size in rotor2 almost has no influence on the performance of rotor1, while the performance of rotor2 is increased about 1.37% at near-stall point when the tip clearance size of rotor1 is increased to 1.0 mm from 0.5 mm. At peak efficiency condition, the tip clearance size variation in rotor1 has remarkable influence on the tip leakage vortex intensity, onset point and trajectory in rotor1, but has little influence on those in rotor2. However, the tip clearance size variation in rotor2 has remarkable effect on those in both rotors. Different tip clearance size combination schemes can impact the stall-free characteristic in the counter-rotating axial compressor.

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Fletcher, T. M., and R. E. Brown. "Modelling the interaction of helicopter main rotor and tail rotor wakes." Aeronautical Journal 111, no. 1124 (October 2007): 637–43. http://dx.doi.org/10.1017/s0001924000004814.

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Abstract The mutual interaction between the main rotor and tail rotor wakes is central to some of the most problematic dynamic phenomena experienced by helicopters. Yet achieving the ability to model the growth and propagation of helicopter rotor wakes with sufficient realism to capture the details of this interaction has been a significant challenge to rotorcraft aerodynamicists for many decades. A novel computational fluid dynamics code tailored specifically for rotorcraft applications, the vorticity transport model, has been used to simulate the interaction of the rotors of a helicopter with a single main rotor and tail rotor in both hover and low-speed quartering flight, and with the tail rotor rotating both top-forward and top-aft. The simulations indicate a significant level of unsteadiness in the performance of both main and tail rotors, especially in quartering flight, and a sensitivity to the direction of rotation of the tail rotor. Although the model thus captures behaviour that is similar to that observed in practice, the challenge still remains to integrate the information from high fidelity simulations such as these into routine calculations of the flight dynamics of helicopters.

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Lei, Yao, and Rongzhao Lin. "Effect of wind disturbance on the aerodynamic performance of coaxial rotors during hovering." Measurement and Control 52, no. 5-6 (April 25, 2019): 665–74. http://dx.doi.org/10.1177/0020294019834961.

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The ability to resist the effect of wind disturbance is vital for micro air vehicles. As the most compact rotor configuration for micro air vehicles, coaxial rotors will be the preferred choice for this type of devices. In this paper, the aerodynamic performance of the coaxial rotors considering the wind gust is presented with both experiments and simulations. First, effect of wind disturbances on the micro air vehicles flight was introduced. Then, low-speed wind tunnel tests were performed on a coaxial rotor with a spacing 0.39 R to obtain the performance in both horizontal and vertical wind of 0–5 m/s with the revolutions per minute ranging from 1500 to 2400. Finally, computational fluid dynamics simulations, as a means of visualizing the flow field to compensate the intuition of the experimental data, were applied by using the sliding mesh to capture the detailed interference of flow field with the distributions of streamline and velocity vector. Compared with wind tunnel tests, simulation results were highly consistent with experiments that allow to capture the flow details around the rotor tip effectively. In addition, the aerodynamic performance was deteriorated by vortices moving or deforming around the blade tip. Also, coaxial rotors can effectively resist the wind disturbance in the horizontal direction while the rotor performance was found to be declined in the vertical wind.

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Lei, Yao, Yiqiang Ye, and Zhiyong Chen. "Horizontal Wind Effect on the Aerodynamic Performance of Coaxial Tri-Rotor MAV." Applied Sciences 10, no. 23 (December 1, 2020): 8612. http://dx.doi.org/10.3390/app10238612.

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The coaxial Tri-rotor micro air vehicle (MAV) is composed of three coaxial rotors where the aerodynamic characteristics of is complicated in flight especially when the wind effect is introduced. In this paper, the hovering performance of a full-scale coaxial Tri-rotor MAV is analyzed with both the simulations and wind tunnel experiments. Firstly, the wind effect on the aerodynamic performance of coaxial Tri-rotor MAV is established with different rotor speed (1500–2300 rpm) and horizontal wind (0–4 m/s). Secondly, the thrust and power consumption of coaxial Tri-rotor (L/D = 1.6) were obtained with low-speed wind tunnel experiments. Furthermore, the streamline distribution, pressure distribution, velocity contour and vortex distribution with different horizontal wind conditions are obtained by numerical simulations. Finally, combining the experiment results and simulation results, it is noted that the horizontal wind may accelerate the aerodynamic coupling, which resulting in the greater thrust variation up to 9% of the coaxial Tri-rotor MAV at a lower rotor speed. Moreover, the aerodynamic performance is decreased with more power consumption at higher rotor speed where the wind and the downwash flow are interacted with each other. Compared with no wind flow, the shape of the downwash flow and the deformation of the vortex affect the power loading and figure of metric accordingly.

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Sun, Zhenye, Wei Jun Zhu, Wen Zhong Shen, Wei Zhong, Jiufa Cao, and Qiuhan Tao. "Aerodynamic Analysis of Coning Effects on the DTU 10 MW Wind Turbine Rotor." Energies 13, no. 21 (November 3, 2020): 5753. http://dx.doi.org/10.3390/en13215753.

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The size of wind turbine rotors is still rapidly increasing, though many technical challenges emerge. Novel rotor designs emerge to satisfy this up-scale trend, such as downwind load-aligned concepts, which orients the loads along the blade spanwise to greatly decrease the bending moments at the root. As the studies on the aerodynamics of these rotor concepts using 3D body-fitted mesh are very limited, this paper establishes different cone configurations based on the DTU 10 MW reference rotor and conducts a series of simulations. It is found that the cone angle and the distance from the blade section to the tip vortex are two deterministic factors on conning. Upwind rotors have larger power output, less thrust, smaller wake deficit, and smaller influencing area than downwind rotors of the same size, which provides superior aerodynamic priority and benefits wind farm design. The largest upwind cone angle of 14.03°, among the cases studied, leads to the highest torque to thrust ratio which is 3.63% higher than the baseline rotor. The downwind load-aligned rotor, designed to reduce the blade root bending moments at large wind speed, performs worse at the present simulation conditions than an upwind rotor of the same size.

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Benti, Gudeta Berhanu, Rolf Gustavsson, and Jan-Olov Aidanpää. "Speed-Dependent Bearing Models for Dynamic Simulations of Vertical Rotors." Machines 10, no. 7 (July 10, 2022): 556. http://dx.doi.org/10.3390/machines10070556.

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Many dynamic simulations of a rotor with a journal bearing employ non-linear fluid-film lubrication models and calculate the bearing coefficients at each time step. However, calculating such a simulation is tedious and computationally expensive. This paper presents a simplified dynamic simulation model of a vertical rotor with tilting pad journal bearings under constant and variable (transient) rotor spin speed. The dynamics of a four-shoes tilting pad journal bearing are predefined using polynomial equations prior to the unbalance response simulations of the rotor-bearing system. The Navier–Stokes lubrication model is solved numerically, with the bearing coefficients calculated for six different rotor speeds and nine different eccentricity amplitudes. Using a MATLAB inbuilt function (poly53), the stiffness and damping coefficients are fitted by a two-dimensional polynomial regression and the model is qualitatively evaluated for goodness-of-fit. The percentage relative error (RMSE%) is less than 10%, and the adjusted R-square (Radj2) is greater than 0.99. Prior to the unbalance response simulations, the bearing parameters are defined as a function of rotor speed and journal location. The simulation models are validated with an experiment based on the displacements of the rotor and the forces acting on the bearings. Similar patterns have been observed for both simulated and measured orbits and forces. The resultant response amplitudes increase with the rotor speed and unbalanced magnitude. Both simulation and experimental results follow a similar trend, and the amplitudes agree with slight deviations. The frequency content of the responses from the simulations is similar to those from the experiments. Amplitude peaks, which are associated with the unbalance force (1 × Ω) and the number of pads (3 × Ω and 5 × Ω), appeared in the responses from both simulations and experiments. Furthermore, the suggested simulation model is found to be at least three times faster than a classical simulation procedure that used FEM to solve the Reynolds equation at each time step.

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Lei, Yao, and Mingxin Cheng. "Aerodynamic performance of a Hex-rotor unmanned aerial vehicle with different rotor spacing." Measurement and Control 53, no. 3-4 (January 31, 2020): 711–18. http://dx.doi.org/10.1177/0020294019901313.

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In this paper, an attempt was made to obtain the aerodynamic performance of a Hex-rotor unmanned aerial vehicle with different rotor spacing. The hover efficiency of the Hex-rotor unmanned aerial vehicle is analyzed by both experimental tests and numerical simulations. First, a series of index to characterize the aerodynamic performance of the Hex-rotor unmanned aerial vehicle are analyzed theoretically, and then both tests and simulations on a Hex-rotor unmanned aerial vehicle with different rotor spacing ratio ( i = 0.50, 0.56, 0.63, 0.71, 0.83) were presented in details. For a custom-designed test platform, the thrust, power loading and hover efficiency of the Hex-rotor unmanned aerial vehicle were obtained in this paper. Finally, computational fluid dynamics simulations are performed to obtain the streamline distributions of the flow field, pressure and velocity contour of the Hex-rotor unmanned aerial vehicle. Results show that the aerodynamic performance of the Hex-rotor unmanned aerial vehicle is varied by changing the rotor spacing. Specifically, the smaller rotor spacing may improve the aerodynamic performance of the Hex-rotor unmanned aerial vehicle by increasing the rotor interferences. In the meantime, the effects of mutual interference between the rotors are gradually reduced with the increase of the rotor spacing. Moreover, the uniformity of the streamline distribution, the shape and the symmetry of the vortex are necessary conditions for the Hex-rotor unmanned aerial vehicle to generate a larger thrust. It was also noted that the thrust increased by 5.61% and the overall efficiency increased by about 8.37% at i = 0.63 for the working mode (2200 r/min), which indicated that the rotor spacing ratio at i = 0.63 obtained a best aerodynamic performance.

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Більше джерел

Дисертації з теми "Simulations rotor"

Narejo, Abdul Ahad. "3D design and simulations of NASA rotor 67." Thesis, University West, Department of Engineering Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-814.

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In this master\2019s thesis work, research has been carried out to develop an automated and parameterized programming model in Matlab to generate a standard journal file, which can read by Gambit and produce a meshed 2D and 3D blade. This file then can be exported into mesh-formatted file for fluent for further simulations and numerical results.

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Roca, León Enric. "Simulations aéro-mécaniques pour l'optimisation de rotors d'hélicoptère en vol d'avancement." Thesis, Nice, 2014. http://www.theses.fr/2014NICE4076.

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Un cadre d'optimisation multi-Objectif pour les pales d'hélicoptère est développé en utilisant des modèles de simulation de haute fidélité. Des fonctions objectives caractérisant la performance de l'hélicoptère en vol stationnaire et d'avancement sont retenues. Deux solveurs sont utilisés afin de prédire la performance du rotor: le code général HOST et le solveur CFD elsA. Le premier axe de recherche porte sur la caractérisation de la précision des méthodes de prédiction. L'influence de la prise en compte de la souplesse de la pale, du trim rotor et/ou de l'utilisation de modélisations aérodynamiques simplifiées est caractérisée pour chaque cas de vol en utilisant des mesures en soufflerie. Un cadre numérique adapté à l'optimisation est développé. Le deuxième axe de recherche porte sur des techniques d'optimisation multi-Objectif de pales en vol stationnaire et d'avancement. Deux algorithmes novateurs basés sur la compétition (Jeux de Nash) et la coopération (Descente à Gradients Multiples) sont présentés comme des alternatives aux approches traditionnelles pour traiter le problème multi-Objectif. Afin de réduire le coût des simulations, un cadre de simulation basé sur des métamodèles est développé y compris une stratégie multi-Fidélité pour prédire la performance du rotor en vol d'avancement. Ces techniques sont appliquées à un cas réaliste de rotor, en utilisant des simulations CFD trimmées avec pale souple pour le cas du vol d'avancement et des simulations CFD avec pale rigide en vol stationnaire. Les résultats sont ensuite analysés, démontrant le potentiel de ces techniques pour l'obtention de conceptions réalistes représentant des bons compromis entre les objectifs
This work addresses the development of a multi-Objective optimization framework for helicopter rotor blades using high-Fidelity simulation models. In particular, objective functions corresponding to hover and forward flight are considered. Two solvers are used to predict the rotor performance: the comprehensive rotor code HOST and the Computational Fluid Dynamics (CFD) solver elsA. The first research axis of this work is the characterization of the accuracy of each available prediction method. The influence of considering the blade elasticity, the rotor trim and/or simplified aerodynamics is characterized for each flight case using wind-Tunnel data. As a result, a numerical framework adapted to the optimization is developed. The second part of this work concerns the formulation and development of techniques adapted to the multi-Objective optimization of rotor blades in hover and in forward flight. Innovative algorithms based on competition (Nash Games) and cooperation (Multi-Gradient Descent) are presented as alternatives to traditional multi-Objective approaches. In order to reduce the simulation costs, a surrogate-Based framework is developed, including a multi-Fidelity strategy to predict the rotor performance in forward flight. These techniques are finally applied to a realistic rotor, considering trimmed elastic CFD computations in the forward flight case and rigid blade CFD computations in the hover case. The results are subsequently analyzed, demonstrating the potential of these techniques to obtain realistic designs realizing interesting trade-Offs

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Gupta, Vinit. "Quad tilt rotor simulations in helicopter mode using computational fluid dynamics." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3172.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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Zhong, B. "Implicit multi-block Euler/Navier-Stokes simulations for hovering helicopter rotor." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/10754.

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A three dimensional implicit multiblock Navier-Stokes solver for hovering rotor vortical flow simulations has been developed. The governing equations used are cast in an attached blade rotating frame. Two formulations of the governing equations using the relative or absolute velocity as variables respectively are employed and investigated. The Osher's approximate Riemann solver is used for the convective fluxes evaluation. A modified MUSCL scheme is employed for improving the accuracy of the discretisation for the in viscid fluxes. A Block Incomplete Lower and Upper Decomposition (BILU) is adopted for solving the linear system resulted from the use of an implicit scheme. Special treatment for the terms, including extra flux terms and source terms, arising from the non- inertial reference system are implemented. A multiblock technique is used to obtain the exibility for quality grid generation. The suitability of different grid topologies for vortex wake capturing is demonstrated. Numerical tests show that significant improvement in computational efficiency is achieved by utilising the BILU implicit scheme in both fixed wing and hovering rotor calculations. Numerical simulations also demonstrate Navier-Stokes solutions give more accurate results than that from Euler solutions, especially in transonic tip speed cases. Computed results including surface pressure distributions and tip vortex trajectories are compared with the experimental data, which shows that the developed solver and the numerical scheme can simulate hovering rotor flows with good accuracy.

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Zhong, Bowen. "Implicit multi-block Euler/Navier-Stokes simulations for hovering helicopter rotor." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/10754.

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Анотація:

A three dimensional implicit multiblock Navier-Stokes solver for hovering rotor vortical flow simulations has been developed. The governing equations used are cast in an attached blade rotating frame. Two formulations of the governing equations using the relative or absolute velocity as variables respectively are employed and investigated. The Osher's approximate Riemann solver is used for the convective fluxes evaluation. A modified MUSCL scheme is employed for improving the accuracy of the discretisation for the in viscid fluxes. A Block Incomplete Lower and Upper Decomposition (BILU) is adopted for solving the linear system resulted from the use of an implicit scheme. Special treatment for the terms, including extra flux terms and source terms, arising from the non-inertial reference system are implemented. A multiblock technique is used to obtain the exibility for quality grid generation. The suitability of different grid topologies for vortex wake capturing is demonstrated. Numerical tests show that significant improvement in computational efficiency is achieved by utilising the BILU implicit scheme in both fixed wing and hovering rotor calculations. Numerical simulations also demonstrate Navier-Stokes solutions give more accurate results than that from Euler solutions, especially in transonic tip speed cases. Computed results including surface pressure distributions and tip vortex trajectories are compared with the experimental data, which shows that the developed solver and the numerical scheme can simulate hovering rotor flows with good accuracy.

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JACQUES, REMI. "Simulations numeriques d'ecoulements transitionnels et turbulents dans des configurations de type rotor-stator." Paris 11, 1997. http://www.theses.fr/1997PA112386.

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Ce travail de these porte sur l'etude numerique des ecoulements transitionnels et turbulents dans une cavite confinee formee de deux disques coaxiaux dont l'un est en rotation uniforme autour de son axe de revolution (rotor), et l'autre stationnaire (stator). Les simulations numeriques sont effectuees sous l'hypothese d'axisymetrie de l'ecoulement instantane. On utilise alors un code de calcul parallelise integrant une decomposition de domaine. Plusieurs caracteristiques des ecoulements entre deux disques tournants sont reproduites : existence de couches limites sur les deux disques tournants, separees par un region centrale de l'ecoulement en rotation moyenne uniforme, caractere plus instable de la couche limite liee au disque fixe. L'existence d'un regime d'ondes inertielles a egalement ete mis en evidence dans le cur de la cavite lorsque l'ecoulement est turbulent dans la couche limite liee au disque fixe. L'etude des equations de transport des tensions de reynolds montre que la rotation modifie les distributions spatiales de certains termes intervenant dans les bilans associes a ces equations. Ils mettent egalement en evidence les limitations de l'hypothese d'axisymetrie qui modifie alors des caracteristiques intrinseques de la turbulence. Des simulations numeriques tridimensionnelles avec un code de calcul parallelise sont alors effectuees pour le regime d'ecoulement laminaire instationnaire. Ces premieres simulations ont montre que l'hypothese d'axisymetrie stabilisait l'ecoulement. Enfin, les resultats de simulation numerique sont confrontes a des resultats fournis par une modelisation de la turbulence de type k - et des resultats experimentaux. Les deux methodologies numeriques fournissent des resultats relativement proches concernant les distributions de vitesse moyenne.

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Parthasarathy, Nikhil Kaushik. "An efficient algorithm for blade loss simulations applied to a high-order rotor dynamics problem." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/189.

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Анотація:

In this thesis, a novel approach is presented for blade loss simulation of an aircraft gas turbine rotor mounted on rolling element bearings with squeeze film dampers, seal rub and enclosed in a flexible housing. The modal truncation augmentation (MTA) method provides an efficient tool for modeling this large order system with localized nonlinearities in the ball bearings. The gas turbine engine, which is composed of the power turbine and gas generator rotors, is modeled with 38 lumped masses. A nonlinear angular contact bearing model is employed, which has ball and race degrees of freedom and uses a modified Hertzian contact force between the races and balls and for the seal rub. This combines a dry contact force and viscous damping force. A flexible housing with seal rub is also included whose modal description is imported from ANSYS. Prediction of the maximum contact load and the corresponding stress on an elliptical contact area between the races and balls is made during the blade loss simulations. A finite-element based squeeze film damper (SFD), which determines the pressure profile of the oil film and calculates damper forces for any type of whirl orbit is utilized in the simulation. The new approach is shown to provide efficient and accurate predictions of whirl amplitudes, maximum contact load and stress in the bearings, transmissibility, thermal growths, maximum and minimum damper pressures and the amount of unbalanced force for incipient oil film cavitation. It requires about 4 times less computational time than the traditional approaches and has an error of less than 5 %.

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Wells, Jesse Buchanan. "Effects of Turbulence Modeling on RANS Simulations of Tip Vortices." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34343.

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Анотація:

The primary purpose of this thesis is to quantify the effects of RANS turbulence modeling on the resolution of free shear vortical flows. The simulation of aerodynamic wing-tip vortices is used as a test bed. The primary configuration is flow over an isolated finite wing with aspect ratio, , and Reynolds number, . Tip-vortex velocity profiles, vortex core and wake turbulence levels, and Reynolds stresses are compared with wind tunnel measurements. Three turbulence models for RANS closure are tested: the Lumley, Reece, and Rodi full Reynolds stress transport model and the Sparlart-Allmaras model with and without a proposed modification. The main finding is that simulations with the full Reynolds stress transport model show remarkable mean flow agreement in the vortex and wake due to the proper prediction of a laminar vortex core. Simulations with the Spalart-Allmaras model did not indicate a laminar core and predicted over-diffusion of the tip-vortex. Secondary investigations in this work include the study of wall boundary layer treatment and simulating the wake-age of an isolated rotorcraft in hover using a steady-state RANS solver. By comparing skin friction plots over the NACA 0012 airfoil, it is shown that wall functions are most effective in the trailing edge half of the airfoil, while high velocity gradient and curvature of the leading edge make them more vulnerable to discrepancies. The rotorcraft simulation uses the modified Spalart-Allmaras turbulence model and shows proper, qualitative, resolution of the interaction between the vortex sheet and the tip vortex.
Master of Science

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Chatzisavvas, Ioannis [Verfasser], Bernhard [Akademischer Betreuer] Schweizer, and Wolfgang [Akademischer Betreuer] Seemann. "Efficient Thermohydrodynamic Radial and Thrust Bearing Modeling for Transient Rotor Simulations / Ioannis Chatzisavvas ; Bernhard Schweizer, Wolfgang Seemann." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2018. http://d-nb.info/116838088X/34.

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Verley, Simon. "Evaluation du couple "champ lointain" d'un rotor d'hélicoptère en vol stationnaire : analyse de résultats issus de simulations numériques de mécanique des fluides." Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00904918.

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Анотація:

Dans cette thèse, une formulation pour l'extraction du couple " champ lointain " d'un rotor d'hélicoptère en vol stationnaire est présentée. Cette formulation est dérivée de la méthode d'extraction de la traînée " champ lointain " d'un avion, basée sur les travaux de van der Vooren et Destarac [?, ?, ?]. Un outil développé à l'Onera à partir de cette théorie permet de donner une analyse complète de la traînée aérodynamique d'un avion. Il est basé sur l'analyse physique et locale de l'écoulement calculé autour de l'aéronef, et décompose la traînée totale, aussi appelée traînée mécanique, en composantes physiques. Ces composantes physiques peuvent être définies comme suit : 1) la traînée d'onde, 2) la traînée visqueuse, 3) la traînée induite. L'adaptation de la méthode d'extraction de la traînée d'un avion à un rotor en vol stationnaire nécessite l'utilisation du couple rotor à la place de la traînée de l'avion, ce qui donne la décomposition suivante : 1) le couple d'onde, 2) le couple visqueux, 3) le couple induit. Les simulations de rotor diffèrent de celles de l'avion dans la mesure où les équations d'Euler (ou RANS) ne sont pas écrites dans le même repère de référence : les simulations d'avion utilisent généralement une formulation en vitesse relative tandis que les simulations d'un rotor d'hélicoptère utilisent la vitesse absolue projetée dans le repère relatif. Cette différence conduit à deux formulations différentes des équations de l'écoulement, et nécessairement deux formulations différentes de l'extraction de la traînée ou du couple. Ce changement de repère implique aussi des changements dans les quantités thermodynamiques utilisées, en particulier l'utilisation de la rothalpie à la place de l'enthalpie d'arrêt pour déterminer le couple dû aux phénomènes irréversibles. Une application de cette méthode est présentée sur un rotor quadripale créé pour cette étude et montre comment cette nouvelle approche peut améliorer la précision de l'extraction des performances d'un rotor à partir de résultat issu de la simulation numérique.

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Книги з теми "Simulations rotor"

Center, Ames Research, ed. Three-dimensional Navier-Stokes simulations of turbine rotor-stator interaction. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1988.

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Boretti, A. A. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. [Cleveland, Ohio: National Aeronautics and Space Administration, Lewis Research Center, Institute for Computational Mechanics in Propulsion, 1990.

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Boretti, A. A. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. Cleveland, Ohio: Lewis Research Centre, 1990.

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Lewis Research Center. Institute for Computational Mechanics in Propulsion., ed. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. [Cleveland, Ohio: National Aeronautics and Space Administration, Lewis Research Center, Institute for Computational Mechanics in Propulsion, 1990.

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Boretti, A. A. Two-dimensional Euler and Navier Stokes time accurate simulations of fan rotor flows. Cleveland, Ohio: NASA Lewis Research Center, Institute for Computational Mechanics in Propulsion, 1990.

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1950-, Hill Gary, and Ames Research Center, eds. Comparisons of elastic and rigid blade-element rotor models using parallel processing technology for piloted simulations. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1991.

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P, Friedmann Peretz, and Ames Research Center, eds. Aeroelastic simulation of higher harmonic control. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1994.

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Частини книг з теми "Simulations rotor"

Neuhauser, Magdalena, Francis Leboeuf, Jean-Christophe Marongiu, Etienne Parkinson, and Daniel Robb. "Simulations of Rotor–Stator Interactions with SPH-ALE." In Advances in Hydroinformatics, 349–61. Singapore: Springer Singapore, 2013. http://dx.doi.org/10.1007/978-981-4451-42-0_29.

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Song, An, Xiang Luo, Zhongliang He, and Jian He. "Numerical Investigation on Flow and Heat Transfer of a Rotor–Stator Cavity with Labyrinth Seal." In Computational and Experimental Simulations in Engineering, 797–814. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-42515-8_56.

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Hirose, Koichiro, Koji Fukudome, and Makoto Yamamoto. "Three-Dimensional Simulation of Ice Crystal Trajectory with State Change Around Rotor Blade of Axial Fan." In Computational and Experimental Simulations in Engineering, 235–43. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67090-0_20.

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Landi, Giacomo, Travis Shive, and Fabrizio Mandrile. "Rotor-Dynamic Computer Simulations of Rolling Bearing in High-Speed Rotating Machinery." In Proceedings of the 9th IFToMM International Conference on Rotor Dynamics, 1889–98. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-06590-8_156.

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More, Shubhali, Amit Kumar, and A. M. Pradeep. "Numerical Simulations on Performance of a Hybrid and a Tandem Rotor." In Proceedings of the National Aerospace Propulsion Conference, 15–33. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2378-4_2.

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Gorasso, Luca, Liqin Wang, and Chiara Gorasso. "Geometrical Optimization of Hydrodynamic Journal Bearings with Validated Simulations and Artificial Intelligence Tools." In Proceedings of the 9th IFToMM International Conference on Rotor Dynamics, 1057–67. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-06590-8_86.

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Surrey, S., J. H. Wendisch, and F. Wienke. "Coupled Fluid-Structure Simulations of a Trimmed Helicopter Rotor in Forward Flight." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 359–68. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-27279-5_32.

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Giangaspero, G., M. Almquist, K. Mattsson, and E. van der Weide. "Unsteady Simulations of Rotor Stator Interactions Using SBP-SAT Schemes: Status and Challenges." In Lecture Notes in Computational Science and Engineering, 247–55. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19800-2_21.

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Abo-Serie, Essam, and Elif Oran. "Flow Simulation of a New Horizontal Axis Wind Turbine with Multiple Blades for Low Wind Speed." In Springer Proceedings in Energy, 93–106. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-30960-1_10.

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AbstractIn this paper, a new design of a small horizontal-axis wind turbine is introduced. The design is based on the authors’ patent, which uses permanent magnets impeded into a shroud that holds the rotor blades. The generator coils are installed on a fixed diffuser that houses the rotor and acts as a wind concentrator. Therefore, the new design has no hub and is based on direct coupling for electricity generation. The main features of the design have been explored to highlight the advantages with a focus on how the new design can be integrated with the recent development of green buildings. The effect of increasing the number of blades and blade chord distribution on turbine performance has been investigated for the new turbine. Initial design and analysis were carried out using the Blade Element Momentum method and CFD simulations to identify the turbine performance and examine the flow characteristics. The results showed that further energy can be extracted from the turbine if the blade chord size increases at the shroud location and reduces at the turbine hub for a low Tip Speed Ratio TSR within the range of 1.5–3. Furthermore, having more blades can significantly increase the power coefficient and extend the range of operation with a high power coefficient. The number of blades, however, has to be optimised to achieve maximum power relative to the cost. Adding a diffuser and flanges surrounding the turbine can further increase the energy extracted from the wind at low speed.

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Sezer-Uzol, Nilay, Ankur Gupta, and Lyle N. Long. "3-D Time-Accurate Inviscid and Viscous CFD Simulations of Wind Turbine Rotor Flow Fields." In Lecture Notes in Computational Science and Engineering, 457–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-92744-0_57.

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Тези доповідей конференцій з теми "Simulations rotor"

Linton, Daniel, George Barakos, Ronny Widjaja, and Ben Thornber. "A New Actuator Surface Model with Improved Wake Model for CFD Simulations of Rotorcraft." In Vertical Flight Society 73rd Annual Forum & Technology Display, 1–10. The Vertical Flight Society, 2017. http://dx.doi.org/10.4050/f-0073-2017-12010.

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Simulations of rotorcraft operating in unsteady flow-fields, manoeuvring flight, or with complex rotor configurations pose a significant challenge to current simulation methods. Simplified rotor models lack the generality required for the diverse range of operating conditions that a rotor may be exposed to, while higher-fidelity Navier-Stokes CFD simulations with fully-resolved rotors are expensive in terms of computational resources, simulation time, and preprocessing time. Here we present a new rotor and wake model which is fully-coupled to a CFD solver and is based on the actuator surface model. This model is designed to reduce the cost of complex rotorcraft simulations in comparison with fully-resolved simulations and provide greater generality than other rotor models. Results from simulations using the new actuator surface and wake model provide validation of the concept for hover and forward flight. The spanwise loading distribution, thrust coefficient, and wake geometry are shown to be reasonable in comparison with data from experiments, fully-resolved simulations, and prescribed wake models.

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Govindarajan, Bharath, and J. Leishman. "Predictions of Rotor and Rotor/Airframe Configurational Effects on Brownout Dust Clouds." In Vertical Flight Society 70th Annual Forum & Technology Display, 1–27. The Vertical Flight Society, 2014. http://dx.doi.org/10.4050/f-0070-2014-9599.

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Brownout dust cloud simulations were conducted for rotorcraft undergoing representative landing maneuvers, primarily to examine the effects of different rotor placement and rotor/airframe configurations. A time-dependent free-vortex wake for the rotors and surface singularity method for the airframe was employed to represent the carrier phase of the flow. A rigorous coupling strategy for the free-vortex method was developed to include the effects of rotors operating at different rotational speeds, such as a tail rotor. For the dispersed phase of the flow, particle tracking was used to model the dust cloud based on solutions to a decoupled form of Basset-Boussinesq-Oseen equations appropriate to dilute gas–particle suspensions of low Reynolds number Stokes flow. Various techniques were explored to reduce the computational cost of the dust cloud simulations, such as particle clustering and parallel programming using graphic processor units. The predicted flow fields near the ground and resulting dust clouds during the landing maneuvers were analyzed to better understand the physics behind their development, and to examine differences produced by various rotor and airframe configurations. Metrics based on particle counts and particle velocities in the field of view were developed to help quantify the severity of the computed brownout dust clouds. The presence of both a tail rotor and the fuselage was shown to cause both local and global changes to the aerodynamic environment near the ground and also influenced the development of the resulting dust clouds.

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Smith, Brendan, and Farhan Gandhi. "Quadcopter Noise Variation Due to Relative Rotor Phasing." In Vertical Flight Society 80th Annual Forum & Technology Display, 1–11. The Vertical Flight Society, 2024. http://dx.doi.org/10.4050/f-0080-2024-1335.

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This study examines the acoustics in hover for manned-size, multi-rotor, eVTOL aircraft in a quadcopter configuration. The rotors on such larger aircraft could have collective pitch control allowing them to operate at a fixed rotational speed. This paper seeks to explore how the relative phasing between the rotors affects the acoustics. Quadcopters with three different rotors are considered: a baseline solidity σ rotor with number of blades N = 2, a 3σ rotor with number of blades N = 2, and a 3σ rotor with number of blades N = 5. The simulations use the Rensselaer Multicopter Analysis Code (RMAC) for the aerodynamic loads on the blades, coupled to an acoustic propagation code for noise predictions at observers in the plane of the quadcopter and at elevations of 30 deg and 60 deg (below the quadcopter). The starting phase of rotors 2, 3, and 4 are varied relative to rotor 1, resulting in 216 total phasing cases for each rotor. From the simulation results in this study, the range of variation in tonal noise (due to thickness and loading) was between 21-30 dB in overall sound pressure level (OASPL). If there is phase locking between rotors, for 2-bladed rotors orthogonal phasing was generally observed to produce low average noise, while tip-to-tip phasing produced higher averaged noise, but this observation did not hold for 5-bladed rotors. For high-solidity 2-bladed rotors, the unweighted OASPL from tonal noise (thickness and loading) is greater than that from broadband noise, especially in-plane and at low elevation angles. But for high-solidity 5-bladed rotors, OASPL from broadband noise was observed to be higher than from tonal noise.

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Coder, James, and Norman Foster. "Structured, Overset Simulations for the 1st Rotor Hub Flow Workshop." In Vertical Flight Society 73rd Annual Forum & Technology Display, 1–10. The Vertical Flight Society, 2017. http://dx.doi.org/10.4050/f-0073-2017-11999.

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Structured, overset computational fluid dynamics methods are used to simulate a water-tunnel experiment of flow over a rotating, 4-bladed rotor hub at Reynolds numbers near that of full scale. A hybrid RANS/LES method is employed with fifth-order discretization of convective flux terms and second-order time integration to resolve largescale turbulent flow features in the wake. Preliminary simulations on a baseline grid system revealed inadequate grid resolution in the wake region along with contamination from inflow and outflow boundaries being too close to the region of interest. An improved grid system was made based on the lessons learned, and results obtained for this grid are described in detail. Comparison of time-averaged velocities in the wake show an underprediction of the velocity deficit in the mid and far wakes. Frequency spectra of the hub drag loads and downstream wake velocities are presented and compared with experiment.

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Heister, Christoph. "Approximate Transition Prediction for the ONERA 7AD Rotor in Forward Flight using a Structured and Unstructured U/RANS solver." In Vertical Flight Society 72nd Annual Forum & Technology Display, 1–11. The Vertical Flight Society, 2016. http://dx.doi.org/10.4050/f-0072-2016-11374.

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The simulation capabilities of the URANS solvers TAU and FLOWer of DLR have been extended in order to predict the laminar-turbulent transition onset on helicopter rotors. Therefore an approximate method for rotor blade transition prediction (RBT code) has been developed and coupled to the URANS solvers. The RBT code computes laminar boundary layer quantities based on a combined integral/Pohlhausen method. Transition is empirically predicted respecting Tollmien-Schlichting waves, laminar separation bubbles, crossflow, bypass instabilities and attachment line transition. To study the effects of blade-wake/vortex-interactions on the laminar boundary layer stability, the turbulence level of the rotor wake is taken into account for transition prediction. Test computations for two laminar flow airfoils reproduced the transition onset due to longitudinal and crossflow instabilities in close agreement to the experiment. For a helicopter rotor in forward flight, laminar-turbulent simulations were successfully demonstrated for both URANS flow solvers. A broad spectrum of different boundary layer instabilities could be identified at the blades. The predicted laminar flow at the rotor blades reduced the required rotor power by -4.5% at high speed forward flight compared to a fully turbulent simulation. The rotor thrust remained practically unaffected. The results were in good agreement between both URANS flow simulations and the experimental data.

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Lienard, Caroline, Raphaël Fukari, Itham Salah, and Thomas Renaud. "RACER high-speed demonstrator: Rotor and rotor-head wake interactions with tail unit." In Vertical Flight Society 80th Annual Forum & Technology Display, 1–13. The Vertical Flight Society, 2024. http://dx.doi.org/10.4050/f-0074-2018-12699.

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Within the framework of NACOR project in CleanSky 2 AIRFRAME ITD, ONERA and DLR performed parallel investigations dealing with the RACER high-speed demonstrator, and especially with its tail parts, each partner respectively focusing on vertical fins (ONERA) and horizontal stabilizer (DLR). During this design phase, most of the CFD simulations were steady-state and neglected the effect of the rotor (or rotor-head) and of the propellers. It however turned out that the rotor-head had a significant effect on the vertical fins and that it was essential to take into account its rotation in time-accurate simulations: the wake from the rotor-head, the upper deck and the engine cowlings indeed strongly impacts the left vertical fin because of the clockwise rotation of the rotor-head. It induces strong oscillations on the tail unit loads, and the mean tail unit lateral thrust is also significantly increased. Moreover the main conclusions of this 'aerodynamic interactions' investigation are almost identical, no matter what the computed configuration: rotating rotor-head, rotating rotor-head with actuator-disk, rotating full-rotor or rotating full-rotor with propellers effect.

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Misiorowski, Matthew, Assad Oberai, and Farhan Gandhi. "A Computational Study on Rotor Interactional Effects for a Quadcopter in Edgewise Flight." In Vertical Flight Society 80th Annual Forum & Technology Display, 1–12. The Vertical Flight Society, 2024. http://dx.doi.org/10.4050/f-0074-2018-12705.

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This study examines the performance of a quadcopter in edgewise flight conditions with flow simulated using the commercial Navier-Stokes solver, AcuSolve, with a Detached Eddy Simulation (DES) model. The rotating volume around each rotor interfaces with the remainder of the computational domain using a sliding mesh. Simulations were conducted for an AeroQuad Cyclone quadcopter at 10 m/s forward speed, 5 deg nose-down pitch attitude, operating in both cross and plus configurations. From the results it was observed that in the cross configuration, the aft (South) rotors showed a 19% reduction in lift (relative to an isolated rotor at the same forward speed, pitch attitude and RPM), with an associated 3% reduction in torque. The loss in lift was primarily at the front of the aft rotors due to the downwash induced by the forward rotors, therefore reducing the aft rotor nose-up pitching moments by 54% (relative to operation in isolation). In the plus configuration, sections of the East and West rotors close to the aircraft center-body operate in upwash induced by the North rotor, increasing the lift generated by 5.5% and 7.6% respectively, relative to operation in isolation. The South rotor sees both upwash (and increased lift) along the advancing and retreating edges induced by the East and West rotors, as well as downwash at the front (and reduced lift) induced by the North rotor, but no significant overall changes in thrust or torque.

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Ortun, Biel, Mark Potsdam, Khiem Truong, and Hyeonsoo Yeo. "Rotor Loads Prediction on the ONERA 7A Rotor using Loose Fluid/Structure Coupling." In Vertical Flight Society 72nd Annual Forum & Technology Display, 1–21. The Vertical Flight Society, 2016. http://dx.doi.org/10.4050/f-0072-2016-11370.

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This work exploits the ONERA 7A rotor wind tunnel test for comparison with concurrent simulations at the US Army and ONERA. Rotor airloads and structural loads are predicted by coupling Computational Fluid Dynamics (CFD) with rotorcraft comprehensive analysis (CA). Two test points are examined: a high-speed point and a high-thrust point featuring dynamic stall. The contributions of experimental data processing and wind tunnel test stand to improved agreement are shown. Comparisons are shown for airloads, structural loads, surface pressures, rotor controls and power. The use of state-of-the-art CFD/CA coupled tools provides dramatic improvements in agreement with experiment, compared to previous work. The Helios/RCAS coupling used by the US Army has been validated on the 7A rotor, adding to prior published validations on the UH-60A and HART-II rotors. The elsA/HOST coupling used by ONERA has had its latest developments validated as well.

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Zhao, Jinggen, and Chengjian He. "Real-Time Simulation of Coaxial Rotor Configurations with Combined Finite State Dynamic Wake and VPM." In Vertical Flight Society 70th Annual Forum & Technology Display, 1–12. The Vertical Flight Society, 2014. http://dx.doi.org/10.4050/f-0070-2014-9567.

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This paper describes a first-principle based finite state dynamic rotor wake model that addresses the complex aerodynamic interference inherent to coaxial rotor configurations in support of advanced vertical lift aircraft simulation, design, and analysis. The high fidelity rotor dynamic wake solution combines an enhanced real-time finite state dynamic wake model (DYW) with a first-principle based viscous Vortex Particle Method (VPM). The finite state dynamic wake model provides a state-space real-time modeling capability for advanced rotorcraft configurations and VPM provides a first-principle based solution for the complex rotor wake problem without using ad-hoc parameters. To account for the mutual aerodynamic interference between multiple rotors, the finite state dynamic wake model was enhanced with several essential modeling parameters to empirically account for important physical phenomena. These modeling parameters were determined based on high fidelity VPM simulations. The developed methodology provides a first-principle based real-time finite state dynamic wake model suitable for coaxial rotor configurations. To validate the developed model, simulation results for the rotor performance, the rotor wake dynamics, and the flow field of different coaxial rotor configurations in both hover and forward flight conditions were compared with available measured data. The simulation results demonstrate good correlation with the measurements for all the cases evaluated.

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Coder, James, Philip Cross, and Marilyn Smith. "Turbulence Modeling Strategies for Rotor Hub Flows." In Vertical Flight Society 73rd Annual Forum & Technology Display, 1–12. The Vertical Flight Society, 2017. http://dx.doi.org/10.4050/f-0073-2017-11994.

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The influence of turbulence modeling strategy for computational fluid dynamics simulations of rotor hub flows is assessed. Two specific modeling strategies are discussed and applied to a representative rotor hub geometry that was the focus of the First Rotor Hub Flow Prediction Workshop and for which high-Reynolds number force data and wake measurements are available from a water-tunnel experiment. Simulations with both turbulence models were performed on the same structured, overset grid system using the same flow solver. Identical solution strategies were employed, including time accuracy, spatial discretization, and implicit algorithm. Several aspects of the solutions are compared, including mass-flow rate through the domain, unsteady drag characteristics, and unsteady wake characteristics.

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Звіти організацій з теми "Simulations rotor"

Wenren, Yonghu, Joon Lim, Luke Allen, Robert Haehnel, and Ian Dettwiler. Helicopter rotor blade planform optimization using parametric design and multi-objective genetic algorithm. Engineer Research and Development Center (U.S.), December 2022. http://dx.doi.org/10.21079/11681/46261.

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In this paper, an automated framework is presented to perform helicopter rotor blade planform optimization. This framework contains three elements, Dakota, ParBlade, and RCAS. These elements are integrated into an environment control tool, Galaxy Simulation Builder, which is used to carry out the optimization. The main objective of this work is to conduct rotor performance design optimizations for forward flight and hover. The blade design variables manipulated by ParBlade are twist, sweep, and anhedral. The multi-objective genetic algorithm method is used in this study to search for the optimum blade design; the optimization objective is to minimize the rotor power required. Following design parameter substitution, ParBlade generates the modified blade shape and updates the rotor blade properties in the RCAS script before running RCAS. After the RCAS simulations are complete, the desired performance metrics (objectives and constraints) are extracted and returned to the Dakota optimizer. Demonstrative optimization case studies were conducted using a UH-60A main rotor as the base case. Rotor power in hover and forward flight, at advance ratio 𝜇𝜇 = 0.3, are used as objective functions. The results of this study show improvement in rotor power of 6.13% and 8.52% in hover and an advance ratio of 0.3, respectively. This configuration also yields greater reductions in rotor power for high advance ratios, e.g., 12.42% reduction at 𝜇𝜇 = 0.4.

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Rivera-Casillas, Peter, and Ian Dettwiller. Neural Ordinary Differential Equations for rotorcraft aerodynamics. Engineer Research and Development Center (U.S.), April 2024. http://dx.doi.org/10.21079/11681/48420.

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High-fidelity computational simulations of aerodynamics and structural dynamics on rotorcraft are essential for helicopter design, testing, and evaluation. These simulations usually entail a high computational cost even with modern high-performance computing resources. Reduced order models can significantly reduce the computational cost of simulating rotor revolutions. However, reduced order models are less accurate than traditional numerical modeling approaches, making them unsuitable for research and design purposes. This study explores the use of a new modified Neural Ordinary Differential Equation (NODE) approach as a machine learning alternative to reduced order models in rotorcraft applications—specifically to predict the pitching moment on a rotor blade section from an initial condition, mach number, chord velocity and normal velocity. The results indicate that NODEs cannot outperform traditional reduced order models, but in some cases they can outperform simple multilayer perceptron networks. Additionally, the mathematical structure provided by NODEs seems to favor time-dependent predictions. We demonstrate how this mathematical structure can be easily modified to tackle more complex problems. The work presented in this report is intended to establish an initial evaluation of the usability of the modified NODE approach for time-dependent modeling of complex dynamics over seen and unseen domains.

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Blaylock, Myra L., David Charles Maniaci, and Brian R. Resor. Numerical Simulations of Subscale Wind Turbine Rotor Inboard Airfoils at Low Reynolds Number. Office of Scientific and Technical Information (OSTI), April 2015. http://dx.doi.org/10.2172/1178361.

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Chatagny, Laurent. PR-471-16206-R02 Suction Piping Effect on Pump Performance CFD. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), March 2019. http://dx.doi.org/10.55274/r0011562.

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CFD simulations of pump suction piping coupled to a double suction volute pump were performed with oil at a viscosity of ~90 cSt. Two variants of the suction piping were modeled in order to investigate their effect on the pump performance. Measurement data obtained during PRCI project CPR-15A were used to validate the CFD setup. The CFD results were mostly in line with the measurements, in particular performance and pressure tap values in the suction piping. The pump rotor forces predicted by CFD however showed significant differences to the measured values. The CFD setup presented in this report provides a basis framework for further CFD investigations. This work will benefit the liquids pipeline station designers and operators and also CFD analysts by providing CFD comparisons to benchmark measurements.

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Allen, Luke, Joon Lim, Robert Haehnel, and Ian Dettwiller. Helicopter rotor blade multiple-section optimization with performance. Engineer Research and Development Center (U.S.), June 2021. http://dx.doi.org/10.21079/11681/41031.

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This paper presents advancements in a surrogate-based, rotor blade design optimization framework for improved helicopter performance. The framework builds on previous successes by allowing multiple airfoil sections to designed simultaneously to minimize required rotor power in multiple flight conditions. Rotor power in hover and forward flight, at advance ratio 𝜇 = 0.3, are used as objective functions in a multi-objective genetic algorithm. The framework is constructed using Galaxy Simulation Builder with optimization provided through integration with Dakota. Three independent airfoil sections are morphed using ParFoil and aerodynamic coefficients for the updated airfoil shapes (i.e., lift, drag, moment) are calculated using linear interpolation from a database generated using C81Gen/ARC2D. Final rotor performance is then calculated using RCAS. Several demonstrative optimization case studies were conducted using the UH-60A main rotor. The degrees of freedom for this case are limited to the airfoil camber, camber crest position, thickness, and thickness crest position for each of the sections. The results of the three-segment case study show improvements in rotor power of 4.3% and 0.8% in forward flight and hover, respectively. This configuration also yields greater reductions in rotor power for high advance ratios, e.g., 6.0% reduction at 𝜇 = 0.35, and 8.8% reduction at 𝜇 = 0.4.

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Wissink, Andrew, Jude Dylan, Buvana Jayaraman, Beatrice Roget, Vinod Lakshminarayan, Jayanarayanan Sitaraman, Andrew Bauer, James Forsythe, Robert Trigg, and Nicholas Peters. New capabilities in CREATE™-AV Helios Version 11. Engineer Research and Development Center (U.S.), June 2021. http://dx.doi.org/10.21079/11681/40883.

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CREATE™-AV Helios is a high-fidelity coupled CFD/CSD infrastructure developed by the U.S. Dept. of Defense for aeromechanics predictions of rotorcraft. This paper discusses new capabilities added to Helios version 11.0. A new fast-running reduced order aerodynamics option called ROAM has been added to enable faster-turnaround analysis. ROAM is Cartesian-based, employing an actuator line model for the rotor and an immersed boundary model for the fuselage. No near-body grid generation is required and simulations are significantly faster through a combination of larger timesteps and reduced cost per step. ROAM calculations of the JVX tiltrotor configuration give a comparably accurate download prediction to traditional body-fitted calculations with Helios, at 50X less computational cost. The unsteady wake in ROAM is not as well resolved, but wake interactions may be a less critical issue for many design considerations. The second capability discussed is the addition of six-degree-of-freedom capability to model store separation. Helios calculations of a generic wing/store/pylon case with the new 6-DOF capability are found to match identically to calculations with CREATE™-AV Kestrel, a code which has been extensively validated for store separation calculations over the past decade.

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Allen, Luke, Joon Lim, Robert Haehnel, and Ian Detwiller. Rotor blade design framework for airfoil shape optimization with performance considerations. Engineer Research and Development Center (U.S.), June 2021. http://dx.doi.org/10.21079/11681/41037.

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A framework for optimizing rotor blade airfoil shape is presented. The framework uses two digital workflows created within the Galaxy Simulation Builder (GSB) software package. The first is a workflow enabling the automated creation of a surrogate model for predicting airfoil performance coefficients. An accurate surrogate model for the rapid generation of airfoil coefficient tables has been developed using linear interpolation techniques that is based on C81Gen and ARC2D CFD codes. The second workflow defines the rotor blade optimization problem using GSB and the Dakota numerical optimization library. The presented example uses a quasi-Newton optimization algorithm to optimize the tip region of the UH-60A main rotor blade with respect to vehicle performance. This is accomplished by morphing the blade tip airfoil shape for optimum power, subject to a constraint on the maximum pitch link load.

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Yang, Cheng-I., Minyee Jiang, Christopher J. Chesnakas, and Stuart D. Jessup. Numerical Simulation of Tip Vortices of a Ducted Rotor. Fort Belvoir, VA: Defense Technical Information Center, September 2004. http://dx.doi.org/10.21236/ada426510.

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Carico, Dean, and Singli Garcia-Otero. Tilt Rotor Aircraft Modeling Using a Generic Simulation Structure,. Fort Belvoir, VA: Defense Technical Information Center, December 1995. http://dx.doi.org/10.21236/ada305253.

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Mittal, Rajat. Large-Eddy Simulation of the Tip-Flow of a Rotor in Hover. Fort Belvoir, VA: Defense Technical Information Center, October 2005. http://dx.doi.org/10.21236/ada440555.

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