scholarly journals Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

2021 ◽  
Vol 8 (8) ◽  
pp. 202275
Author(s):  
Liansong Peng ◽  
Mengzong Zheng ◽  
Tianyu Pan ◽  
Guanting Su ◽  
Qiushi Li
Keyword(s):  
Body Weight ◽  
Flow Field ◽  
Numerical Simulations ◽  
Phase Difference ◽  
High Efficiency ◽  
Lift Coefficient ◽  
Aerodynamic Performance ◽  
The Body ◽  
Wing Surface ◽  
Phase Differences

Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference ( γ ) is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at γ = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at γ = 180°, dragonflies generate the same lift as the body weight.

Inspector Quadro - the complex of preparation for the treatment of ectoand endoparasitoses in cats and dogs

2018 ◽  
Vol 12 (2) ◽  
pp. 75-84
Author(s):  
M.V. Arisov ◽  
I.P. Belykh ◽  
V.V. Artemov
Keyword(s):  
Body Weight ◽  
Clinical Picture ◽  
High Efficiency ◽  
The Body ◽  
Negative Effects ◽  
Laboratory Methods ◽  
Diagnosis Of Infection

The purpose of the research: the study of the efficacy of the preparations for veterinary use "Inspector Quadro C" and "Inspector Quadro K" against ecto- and endoparasitoses of dogs and cats. Materials and methods. Studies were conducted on spontaneously infected dogs and cats of different sexes, age, weight and breed. The diagnosis of infection with ectoparasites was made based on the clinical picture and laboratory methods of investigation (microscopy of scrapings taken from ectoparasitized skin areas, examination of the coat for fleas, lice, worms, ixodids). Infection with helminths was established by detecting eggs of helminths in faeces of animals by the method of Füleleborn and mature segments of cestodes. Preparations were applied to the animals by drip application on dry undamaged skin in places inaccessible to licking in a dose of 0.1-0.4 ml per 1 kg of body weight. The results were statistically processed. Results and discussion. "Inspector Quadro S" and "Inspector Quadro K" showed 100% efficacy at sarcoptosis in dogs, notoedrosis in cats, otodectosis in dogs and cats, ixodidoses and entomoses. "Inspector Quadro C" showed a high efficiency (92.3%) at demodecosis in dogs. However, single mites were found in one dog. 100% efficacy of "Inspector Quadro C" and "Inspector Quadro K" has been established against intestinal nematodes and cestodes in dogs and cats. Negative effects of drugs on the body of animals have not been revealed.

scholarly journals Effect of NS-DBD Actuator Parameters on the Aerodynamic Performance of a Flap Lifting Device

2019 ◽  
Vol 9 (23) ◽  
pp. 5213 ◽  
Author(s):  
Kun Chen ◽  
Chen-Yao Wei ◽  
Zhi-Wei Shi
Keyword(s):  
Energy Density ◽  
Flow Field ◽  
Drag Reduction ◽  
Pulse Width ◽  
High Efficiency ◽  
Aerodynamic Drag ◽  
Pulse Discharge ◽  
Excitation Frequency ◽  
Aerodynamic Performance ◽  
Discharge Pulse

The flap lift device is an important part of the conventional configuration of aircrafts and has an important impact on the aerodynamic performance. In this paper, a high-efficiency, simple, and energy-saving nanosecond dielectric barrier discharge (DBD) plasma actuator is placed in the vicinity of the flap lift device to improve the aerodynamic performance of the flap by controlling the flow field. The two-dimensional airfoil GAW-1 and its 29% flap were selected as the research objects, and the nanosecond (NS) DBD actuators were fixed at different locations near the deflection angle of the 10°flap. The excitation frequency, pulse width, and energy density parameters of the pulse discharge were adjusted, and then, the effects of parameter changes on aerodynamic characteristics of the airfoil were studied by numerical simulation. The simulation results show that adjusting the excitation frequency on the aerodynamic drag is weak and that the effect on the aerodynamic lift is obvious. The increase of the discharge pulse width will have a more significant effect on the flow field, i.e., a proper increase of the discharge pulse width can achieve better drag reduction, and increase lift after a stall at a high angle of attack. Although the increase of discharge energy density can strengthen the pulse perturbation effect on the flow field, it also contributes to some adverse effects and has no obvious optimization effect on the control efficiency of lift increase and drag reduction.

Aerodynamics of a half-rotating wing in hovering flight: An integrated study

2021 ◽  
pp. 095441002199654
Author(s):  
Qian Li ◽  
Jiwei Yuan ◽  
Huan Shen ◽  
Jiaguo Deng ◽  
Timothy R Jakobi ◽  
...  
Keyword(s):  
Flow Field ◽  
Vortex Ring ◽  
Lift Force ◽  
Computational Models ◽  
Lift Coefficient ◽  
The Body ◽  
Driving Mechanism ◽  
Hovering Flight ◽  
Flexible Wing ◽  
Rotating Wing

This study introduces a new quasi-flapping wing driving mechanism based on a half-rotating mechanism which is capable of pure rotational flapping rather than the more traditional oscillatory flapping method. Lift models for half-rotating wing (HRW) aircraft in hovering flight are proposed based on the kinematics of a HRW prototype and the flow characteristics near the surface of its wing. Alongside further analytical expressions for lift based on kinematic extractions, computational models and a novel lift validation mechanism are used to reinforce the aerodynamic characteristics of the HRW in hovering flight. The aerodynamics of the HRW are experimentally assessed for different wing layouts and wing materials. Results indicate that the flow field generated by the motion of the wing arranged symmetrically on both sides of the body interfere with each other, causing the average lift coefficient of the paired-wing HRW to be less than that of the single-wing HRW. The average lift coefficient of the flexible wing is larger than that of the rigid wing. In addition, the average lift of the flexible wing increases with increasing flexural compliance within a particular range. Lift forces in different flight conditions are calculated using derived formulas alongside representative computational models, through which the derivation of lift variation for the HRW in hovering flight is validated. The theoretical lift curves show reasonable agreement with numerical simulation results in terms of the time course over one stroke cycle. The mechanisms of the HRW for generation and shedding of vortices in hovering flight are further revealed in computed flow field characteristics results. The velocity vectors of the flow field between the HRW and the symmetrically rotating wing indicate that the HRW with asymmetric rotation can generate lift force effectively. The velocity difference between the wing and the fluid is the key factor influencing the structure of generated vortices. In detailed three-dimensional (3D) vortex flows, our computational fluid dynamics study shows that a horseshoe-shaped vortex is first generated in the early downstroke. The horseshoe-shaped vortex subsequently grows into a doughnut-shaped vortex ring, with a jet stream appearing in its core which forms the downwash. The doughnut-shaped vortex ring eventually elongates into a long arc-shaped wake vortex ring. A large increasing lift force is generated during the upstroke, most likely due to the stable distal attached vortices; and in accordance with this, downwash becomes evident in the vortex ring during the downstroke.

scholarly journals Theoretical and Experimental of Evaluation of Flow Field Over a Double Delta Wing at Supersonic Speeds

2019 ◽  
Vol 8 (2S11) ◽  
pp. 2939-2943
Keyword(s):  
Stainless Steel ◽  
Flow Field ◽  
Numerical Simulations ◽  
Delta Wing ◽  
Angle Of Attack ◽  
Experimental Studies ◽  
The Body ◽  
Experimental Investigations ◽  
Supersonic Speed ◽  
Double Delta Wing

Numerical and experimental investigations of flay over double delta wing at supersonic speed are investigated . For numerical simulations , the body geometry is generated using SolidWorks software , mesh is created using Gambit and solution is obtained using Fluent sofivvare . For the experimental studies , stainless steel model is fabricated and tested in the supersonic Mind tunnel at Mach 2.5 at 0 and 5 angle of attack . The results are presented in the present paper

Effect of Stage Axial Distances on the Aerodynamic Performance of Three-Stage Axial Turbine Using Experimental Measurements and Numerical Simulations

2017 ◽  
Author(s):  
Yang Chen ◽  
Zhuhai Zhong ◽  
Jun Li ◽  
Weijiu Zhou ◽  
Gangyun Zhong ◽  
...  
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Velocity Ratio ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Axial Distance ◽  
Axial Turbine ◽  
Air Turbine ◽  
Aerodynamic Parameters

The stage axial distance significantly influences the aerodynamic performance of turbines under some constraints. Experimental measurements and numerical simulations are used to analyze the effect of stage axial distances on the aerodynamic performance of three-stage axial turbine in this work. The aerodynamic performance of three-stage axial turbine with three different stage axial distances is experimentally measured at the air turbine test rig of Dongfang Steam Turbine Co. LTD. Experimental results show that efficiency increases when the stage axial distance decreases for the geometry under study with relative stage distance ranged from 0.14 to 0.35, and the effect of stage axial distance on the optimization velocity ratio here is very limited. In addition, unsteady Reynolds-Averaged Navier-Stokes (RANS) simulations were carried out with nonlinear harmonic method to analyze the detailed flow field of the experimental three-stage axial turbine. The numerical aerodynamic efficiency of three-stage axial turbine is in good agreement with the experimental data. Furthermore, the small stage axial distance is preferred for the higher efficiency. The detailed flow field and aerodynamic parameters of three-stage axial turbine are also illustrated and discussed.

The Influence of Supersonic Combustion when the Cavity Parameters Changed on the Chamber Wall

2012 ◽  
Vol 468-471 ◽  
pp. 2620-2623
Author(s):  
Peng Gao ◽  
Xin Long Chang ◽  
Shuang Lin Gao ◽  
Jie Tang Zhu
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
High Efficiency ◽  
Supersonic Combustion ◽  
Chamber Wall ◽  
Flame Stability ◽  
Hydrogen Fuel ◽  
Research Results ◽  
Scramjet Combustor ◽  
Air Mixing

In this paper, the detail numerical simulations were performed on the flow field of the scramjet combustor chamber with the hydrogen fuel, when the cavity parameters changed. The research results indicate that the effect of gas and air mixing and flame stability are altered when the parameter of cavity changed. From the research we will better understand the supersonic combustion. The high efficiency flame stabilities can be designed in future.

L-Ascorbic Acid Addition to Chitosan Reduces Body Weight in Overweight Women

2014 ◽  
Vol 84 (1-2) ◽  
pp. 5-11 ◽  
Author(s):  
Eun Y. Jung ◽  
Sung C. Jun ◽  
Un J. Chang ◽  
Hyung J. Suh
Keyword(s):  
Ascorbic Acid ◽  
Body Weight ◽  
Fat Body ◽  
Body Weight Gain ◽  
Skinfold Thickness ◽  
The Body ◽  
Control Group ◽  
Percentage Body Fat ◽  
Overweight Women ◽  
Body Weights

Previously, we have found that the addition of L-ascorbic acid to chitosan enhanced the reduction in body weight gain in guinea pigs fed a high-fat diet. We hypothesized that the addition of L-ascorbic acid to chitosan would accelerate the reduction of body weight in humans, similar to the animal model. Overweight subjects administered chitosan with or without L-ascorbic acid for 8 weeks, were assigned to three groups: Control group (N = 26, placebo, vehicle only), Chito group (N = 27, 3 g/day chitosan), and Chito-vita group (N = 27, 3 g/day chitosan plus 2 g/day L-ascorbic acid). The body weights and body mass index (BMI) of the Chito and Chito-vita groups decreased significantly (p < 0.05) compared to the Control group. The BMI of the Chito-vita group decreased significantly compared to the Chito group (Chito: -1.0 kg/m2 vs. Chito-vita: -1.6 kg/m2, p < 0.05). The results showed that the chitosan enhanced reduction of body weight and BMI was accentuated by the addition of L-ascorbic acid. The fat mass, percentage body fat, body circumference, and skinfold thickness in the Chito and Chito-vita groups decreased more than the Control group; however, these parameters were not significantly different between the three groups. Chitosan combined with L-ascorbic acid may be useful for controlling body weight.

Hand-assisted laparoscopic nephrectomy in morbidly obese patients

2020 ◽  
Vol 99 (6) ◽  
pp. 271-276
Keyword(s):  
Body Weight ◽  
Surgical Technique ◽  
Blood Loss ◽  
Hospital Stay ◽  
Kidney Cancer ◽  
The Body ◽  
Laparoscopic Nephrectomy ◽  
Morbidly Obese ◽  
Obese Patients ◽  
Morbid Obese

Introduction: Prevalence of obesity is 30 % in the Czech Republic and is expected to increase further in the future. This disease complicates surgical procedures but also the postoperative period. The aim of our paper is to present the surgical technique called hand-assisted laparoscopic nephrectomy (HALS), used in surgical management of kidney cancer in morbid obese patients with BMI >40 kg/m2. Methods: The basic cohort of seven patients with BMI >40 undergoing HALS nephrectomy was retrospectively evaluated. Demographic data were analyzed (age, gender, body weight, height, BMI and comorbidities). The perioperative course (surgery time, blood loss, ICU time, hospital stay and early complications), tumor characteristics (histology, TNM classification, tumor size, removed kidney size) and postoperative follow-up were evaluated. Results: The patient age was 38−67 years; the cohort included 2 females and 5 males, the body weight was 117−155 kg and the BMI was 40.3−501 kg/m2. Surgery time was 73−98 minutes, blood loss was 20−450 ml, and hospital stay was 5−7 days; incisional hernia occurred in one patient. Kidney cancer was confirmed in all cases, 48–110 mm in diameter, and the largest removed specimen size was 210×140×130 mm. One patient died just 9 months after the surgery because of metastatic disease; the tumor-free period in the other patients currently varies between 1 and 5 years. Conclusion: HALS nephrectomy seems to be a suitable and safe surgical technique in complicated patients like these morbid obese patients. HALS nephrectomy provides acceptable surgical and oncological results.

HISTOLOGICAL CHANGES IN THE INTESTINES OF POULTRY DURING FODDER INTOXICATION

2020 ◽  
Author(s):  
E.P. Dolgov ◽  
◽  
A.A. Abramov ◽  
E.V. Kuzminova ◽  
E.V. Rogaleva ◽  
...  
Keyword(s):  
Body Weight ◽  
Histological Examination ◽  
Aflatoxin B1 ◽  
Structural Changes ◽  
Clinical Manifestations ◽  
Feed Additives ◽  
The Body ◽  
Histological Changes ◽  
Beet Pulp

The article presents the data on the study of the influence of mycotoxins combination (T-2 toxin at the concentration of 0.095 mg/kg and aflatoxin B1 in the concentration of 0.019 mg/kg) on the body of quails and the results of pharmacocorrection of toxicosis with a complex consisting of beet pulp and lecithin. Structural changes in the intestines of quais at fodder mycotoxicosis are described. The use of antitoxic feed additives in poultry led to a weakening of the action of xenobiotics, which was confirmed by an increase in the safety of poultry and increase in body weight of quails, a decrease in the clinical manifestations of intoxication, as well as in positive changes in the structure of the intestine of the poultry during histological examination.

Defensive activity of Hesperidin against Ciprofloxacin induced hepatic injury in rabbits.

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Hawraa M. Murad ◽  
Tamadhur Hani Hussein ◽  
Audai Sulaiman Khudhair ◽  
Manal Muhi Murad ◽  
Jawad Kadhim Faris
Keyword(s):  
Body Weight ◽  
Bacterial Infections ◽  
Hepatoprotective Activity ◽  
The Body ◽  
Local Breed ◽  
Group 4 ◽  
Group 3 ◽  
Group 2 ◽  
Defensive Activity ◽  
Antioxidant Effects

This study was conducted to find out hepatoprotective activity of hesperidin (HES) 100mg/kg body weight (b.w.) against ciprofloxacin (CPX) 100 mg/kg induced hepatotoxicity in local breed rabbits .CPX is a broad spectrum antibiotic used for treatment of many bacterial infections. Twenty four male rabbits were divided into four groups ,group1: control, (1 ml/kg Saline orally) group 2: CPX (100 mg/kg orally) for (14) consecutive days , group 3: HES (100 mg//kg) orally for (14) consecutive days group 4: CPX (100 mg/kg orally) plus HES (100 mg//kg orally ) for (14) consecutive days. All the rabbits were killed on the (15) day of the experiment, and then the blood, and livers samples were taken. CPX induced hepatotoxicity was proved by a significant (p less than 0.01) reduction in the body weight ,and a significant (p less than 0.01) increased serum aspartate transaminase (AST), alanine transaminase (ALT) , Malonaldehyde enzyme (MAD) and histopathological changes. Protective hepatic toxicity effect and oxidative damage caused by CPX significantly (p less than 0.01) increasing in body weight and significantly (p less than 0.01) decreasing AST , ALT, MAD and improving tissue morphology in HES (100 mg//kg) . These results assure that HES (100 mg//kg) antioxidant effects can protect CPX-induced hepatotoxicity in rabbits.

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