{"title":"Lift Airfoils Close to the Airfoils in a Flow with the Maximum “Critical” Mach Numbers","authors":"A. N. Kraiko, V. A. Shapovalov","doi":"10.1134/S0015462822700057","DOIUrl":null,"url":null,"abstract":"<p>The lift airfoils close to the airfoils optimal with respect to the critical Mach numbers М* of two-dimensional bodies optimal with respect to М* are constructed using the direct method. Their almost zero wave drag coefficients <i>с</i><sub><i>х</i></sub> remain the same not only at the free-stream Mach numbers М<sub>0</sub> which are lower than М* but also at М<sub>0</sub> perceptibly higher than М*. These new lift airfoils differ from the supercritical lift airfoils whose <i>с</i><sub><i>х</i></sub> grow extremely rapidly when М<sub>0</sub> becomes higher than the designed values. At identical thicknesses and М<sub>0</sub> = М* the supercritical lift airfoils implement the greater lift coefficients <i>с</i><sub><i>у</i></sub>. However, due to the difference in the behavior of <i>с</i><sub><i>х</i></sub> at М<sub>0</sub> which are higher than the designed ones, the lift-drag ratio of the supercritical airfoils can become lower for the ratio of <i>с</i><sub><i>у</i></sub> not to <i>с</i><sub><i>х</i></sub>, but even to the coefficient of total drag.</p>","PeriodicalId":560,"journal":{"name":"Fluid Dynamics","volume":"58 1","pages":"128 - 135"},"PeriodicalIF":1.0000,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fluid Dynamics","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1134/S0015462822700057","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MECHANICS","Score":null,"Total":0}
引用次数: 0
Abstract
The lift airfoils close to the airfoils optimal with respect to the critical Mach numbers М* of two-dimensional bodies optimal with respect to М* are constructed using the direct method. Their almost zero wave drag coefficients сх remain the same not only at the free-stream Mach numbers М0 which are lower than М* but also at М0 perceptibly higher than М*. These new lift airfoils differ from the supercritical lift airfoils whose сх grow extremely rapidly when М0 becomes higher than the designed values. At identical thicknesses and М0 = М* the supercritical lift airfoils implement the greater lift coefficients су. However, due to the difference in the behavior of сх at М0 which are higher than the designed ones, the lift-drag ratio of the supercritical airfoils can become lower for the ratio of су not to сх, but even to the coefficient of total drag.
期刊介绍：
Fluid Dynamics is an international peer reviewed journal that publishes theoretical, computational, and experimental research on aeromechanics, hydrodynamics, plasma dynamics, underground hydrodynamics, and biomechanics of continuous media. Special attention is given to new trends developing at the leading edge of science, such as theory and application of multi-phase flows, chemically reactive flows, liquid and gas flows in electromagnetic fields, new hydrodynamical methods of increasing oil output, new approaches to the description of turbulent flows, etc.
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