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Extension of the KDO turbulence/transition model to account for roughness

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Advances in Aerodynamics 2022年第1期4卷 25-38页

作者： Chunfei Fang jinglei xu State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development Sinopec Research Institute of Petroleum EngineeringBeijing100029China School of Energy and Power Engineering Beihang UniversityBeijing100191China Hangzhou Innovation Institute Yuhang Beihang UniversityHangzhou311100China

Wall roughness significantly influences both laminar-turbulent transition process and fully developed turbulence.A wall roughness extension for the KDO turbulence/transition model is *** roughness effect is introduced via the modification of the k andνt boundary *** wall is considered to be lifted to a higher *** difference between the original position and the higher position,named as equivalent roughness height,is linked to the actual roughness *** ratio between the two heights is determined by *** such a roughness extension,the predictions of the KDO RANS model agree well with the measurements of turbulent boundary layer with a sand grain surface,while the KDO transition model yields accurate cross-flow transition predictions of flow past a 6:1 spheroid.

关键词： Transition model Turbulence model Cross-flow transition Wall roughness

On applying the extended intrinsic mean spin tensor to modelling the turbulence in non-inertial frames of reference

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1691-1706页

作者： HUANG YuNing MA HuiYang xu jinglei State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing 100871China College of Physics Graduate University of the Chinese Academy of SciencesBeijing 100049China

Modelling the turbulent flows in non-inertial frames of reference has long been a challenging task. Recently we introduced the notion of the "extended intrinsic mean spin tensor" for turbulence modelling and pointed out that, when applying the Reynolds stress models developed in the inertial frame of reference to model-ling the turbulence in a non-inertial frame of reference, the mean spin tensor should be replaced by the extended intrinsic mean spin tensor to correctly account for the rotation effects induced by the non-inertial frame of reference, to conform in phys-ics with the Reynolds stress transport equation. To exemplify the approach, we conducted numerical simulations of the fully developed turbulent channel flow in a rotating frame of reference by employing four non-linear K-ε models. Our numerical results based on this approach at a wide range of Reynolds and Rossby numbers evince that, among the models tested, the non-linear K-ε model of Huang and Ma and the non-linear K-ε model of Craft, Launder and Suga can better capture the rotation effects and the resulting influence on the structures of turbulence, and therefore are satisfactorily applied to dealing with the turbulent flows of practical interest in engineering. The general approach worked out in this paper is also ap-plied to the second-moment closure and the large-eddy simulation of turbulence.

关键词： turbulence modelling non-inertial frame of reference extended intrinsic mean spin tensor

Numerical investigation of dynamic characteristics of dual throat nozzle and bypass dual throat nozzle in thrust vectoring starting process

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Chinese Journal of Aeronautics 2024年第10期37卷 184-206页

作者： Yuqi ZHANG jinglei xu Minglei CAO Ruifeng PAN Shuai HUANG Key Laboratory of Inlet and Exhaust System Technology of Ministry of Education Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Aeronautics and Astronautics Structures Nanjing 210016China

The Bypass Dual Throat Nozzle(BDTN)is a novel fluidic Thrust Vectoring(TV)nozzle,it switches to TV state by opening the valve in the *** greatly manipulate the BDTN,the dynamic characteristics in the TV starting process should be *** paper conducts numerical simulations to grasp the variation processes of performances and the flow field evolution of BDTN and Dual Throat Nozzle(DTN).The dynamic responses of TV starting in typical DTN models are investigated at ***,the TV starting processes of BDTN in different Nozzle Pressure Ratio(NPR)conditions are simulated,and the valve opening durations(T)are also *** the expected TV direction is achieved in the DTN,the jet is deflected to the opposite direction at the beginning of the dynamic process,which is called the reverse TV ***,this phenomenon disappears in the *** larger injection width of DTN intensifies unsteady oscillations,and the reverse TV phenomenon is *** the BDTN,T determines the delay degree of performance variations compared to the static results,which is called hysteresis *** NPR=10,the hysteresis affects the final stable performance of *** study analyses the dynamic characteristics in DTN and BDTN,laying a foundation for further design of nozzles and control strategies.

关键词： Dual Throat Nozzle(DTN) Bypass Dual Throat Nozzle(BDTN) Dynamic characteristic Thrust vectoring starting process Cavity vortex Hysteresis effect

Design and implementation of rigid-flexible coupling for a half-flexible single jack nozzle

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Chinese Journal of Aeronautics 2016年第6期29卷 1477-1483页

作者： Chen Pengfei Wu Feng xu jinglei Feng xudong Yang Qiao Aviation Key Laboratory of Science and Technology on Aero-Engine Altitude Simulation China Gas Turbine Establishment Aviation Engine Corporation of China Department of Power Engineering Nanjing University of Aeronautics and Astronautics

The aerodynamic design of a rigid-flexible coupling profile is the decisive factor for the flow-field quality of a supersonic free jet wind tunnel nozzle, and its mechanic dynamic features are the key for engineering implementation of continuous Mach number regulations. To fulfill the requirements of a free jet inlet/engine compatibility test within a wide simulation envelop, both uniform flow-fields of continuous acceleration and deceleration are necessary. In this paper, the aerodynamic design methods of an expansion wall and machinery implementation plan for the halfflexible single jack nozzle were researched. The profile control in nozzle flexible plate design was studied with a rigid-flexible coupling method. Design and calculations were performed with the help of numerical simulation. The technique of axial free stretching of the flexible plate was used to improve the matching performance between the designed elasticity profile and the theoretical one, and the rigid-flexible coupling structure was calibrated by wind tunnel tests. Results indicate that the flexible plate aerodynamic design method used here is effective and feasible. Via rigidflexible coupling design, the flexible plate agrees with the rigid body very well, and continuous Mach number changes can be achieved during the tests. The nozzle’s exit flow-field uniformity meets the requirements of China Military Standard(GJB).

关键词： Aerodynamic profile Flow-field quality Free jet Nozzle Rigid-flexible coupling Variable Mach number Wind tunnel

Numerical study of a trapezoidal bypass dual throat nozzle

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Chinese Journal of Aeronautics 2023年第3期36卷 42-62页

作者： Shuai HUANG jinglei xu Kaikai YU Yangsheng WANG Ruifeng PAN Kuangshi CHEN Yuqi ZHANG State Key Laboratory of Mechanics and Control of Aeronautics and Astronautics Structures Nanjing 210016China College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Province Key Laboratory of Aerospace Power System Nanjing 210016China

Bypass Dual Throat Nozzle(BDTN)is a novel type of fluidic thrust vectoring *** improve the infrared stealth performance of BDTN,a nozzle based on BDTN is proposed and numerically *** cross-section along the x-axis of the novel nozzle becomes a trapezoid,which is named“BDTN-TRA.”The main numerical simulation results show that BDTN-TRA can produce a thrust vectoring angle when the upper or lower bypass valve is *** angle difference between the two conditions mentioned above is usually approximately 1°-2°.Even if the two bypasses are closed,BDTN-TRA can produce a small thrust vectoring angle at around 3°-5°.When the sidewall angle increases from 60°to 90°,the thrust coefficient and thrust vectoring angle under each work condition usually decrease.A larger aspect ratio indicates better *** the aspect ratio increases over 7.2,the performance of BDTN-TRA is quite close to that of BDTN with rectangular cross-sections at the same aspect *** features will benefit the control and trimming for future aircraft design,especially for the flying wing layout *** but not least,BDTN-TRA has a more extraordinary mixing performance compared with *** distributions of static temperature and axial velocity along the x-axis of BDTN-TRA with sidewall angle of 60°decrease faster than those of *** the total temperature of the inlet equals 1600 K,the static temperature difference between BDTN-TRA with sidewall angles of 60°and 90°is over 360 K at twice the length of the nozzle downstream of the nozzle exit,which is the reflection for excellent infrared stealth for the fighter.

关键词： Bypass dual throat nozzle Infrared stealth performance Mixing performance Trapezoidal cross-sections Thrust vectoring

Applications of URANS on predicting unsteady turbulent separated flows

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Acta Mechanica Sinica 2009年第3期25卷 319-324页

作者： jinglei xu Huiyang Ma Department of Physics, Graduate University of the Chinese Academy of Sciences, 100049 Beijing, China Department of Physics Graduate University of the Chinese Academy of Sciences 100049 Beijing China

Accurate prediction of unsteady separated turbulent flows remains one of the toughest tasks and a practi cal challenge for turbulence modeling. In this paper, a 2D flow past a circular cylinder at Reynolds number 3,900 is numerically investigated by using the technique of unsteady RANS （URANS）. Some typical linear and nonlinear eddy viscosity turbulence models （LEVM and NLEVM） and a quadratic explicit algebraic stress model （EASM） are evaluated. Numerical results have shown that a high-performance cubic NLEVM, such as CLS, are superior to the others in simulating turbulent separated flows with unsteady vortex shedding.

关键词： URANS Nonlinear eddy viscosity turbulencemodel ,Separated flows Circular cylinder

5-Formylcytosine and 5-Carboxylcytosine Significantly Reduce the Catalytic Activity of Hhal DNA Methyltransferase

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Chinese Journal of Chemistry 2017年第6期35卷 853-856页

作者： Tingting Hong Fan Wu Boshi Fu Yushu Yuan jinglei xu Tianlu Wang Xiang Zhou College of Chemistry and Molecular Sciences The lnstitute for Advanced Studies Wuhan University Wuhan Hubei 430072 China

DNA methylation is an essential epigenetic modification, and found to be dynamically changed due to the ob- servation of active DNA demethylation. During active demethylation, 5-methylcytosine （5mC） was oxidized step- wise by ten-eleven translocation （TET） enzymes into 5-hydroxymethylcytosine （5hmc）, 5-formylcytosine （5fC）, and 5-carboxylcytosine （5caC）. Then, the subsequent excision of 5fC and 5caC combined with base excision repair further restored cytosine, which completes the demethylation process. Here, we report that 5-formylcytosine and 5-carboxylcytosine significantly reduce the activity of HhaI DNA methyltransferase to methylate target cytosines when present on the hemi-modified sequence of the complementary DNA. This finding demonstrates that 5fC and 5caC function as more than intermediates for active DNA demethylation.

关键词： 5-formylcytosine 5-carboxylcytosine Hhal methyltransferase base flipping

三维并联式TBCC发动机排气系统设计与实验

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航空动力学报 2018年第9期33卷 2268-2277页

作者：花文达徐惊雷南京航空航天大学能源与动力学院江苏省航空动力系统重点实验室南京210016

为实现三维并联式TBCC排气系统的设计,利用基于二维最大推力理论的密切法设计了圆转矩变截面非对称冲压发动机喷管,并在冲压发动机喷管上壁面为三维曲面的条件下,利用转动加滑动共用面的调节方式实现了涡喷发动机喷管的内型面设计及其... 详细信息

为实现三维并联式TBCC排气系统的设计,利用基于二维最大推力理论的密切法设计了圆转矩变截面非对称冲压发动机喷管,并在冲压发动机喷管上壁面为三维曲面的条件下,利用转动加滑动共用面的调节方式实现了涡喷发动机喷管的内型面设计及其喉道面积的调节,从而完成了排气系统设计。随后对设计结果进行了冷流实验验证。结果表明,这种排气系统设计方法具有可行性。在冲压单独工作状态,壁面压力分布的数值计算与实验结果吻合较好,相对方均根偏差低于10.8%;在涡喷单独工作状态及共同工作状态,上壁面压力在激波附面层干扰区域内偏差较大,最大相对偏差可达30.6%。但壁面压力分布的数值计算与实验结果的整体变化趋势一致。

关键词：涡轮基组合循环(TBCC) 三维排气系统喷管设计喉道调节冷流实验

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基于膨胀度可控的SERN设计及试验验证

航空学报 2014年第1期35卷 125-131页

作者：赵强徐惊雷于洋南京航空航天大学能源与动力学院江苏南京210016

单边膨胀喷管(SERN)是超燃冲压发动机的关键部件,由于其几何非对称,在发动机点火/熄火瞬间,SERN会产生较大的冷热态俯仰力矩差,影响飞行器的稳定性。现有解决方法主要是利用几何/气动调节方式,但都有不利影响。本文提出了基于膨胀度可控... 详细信息

单边膨胀喷管(SERN)是超燃冲压发动机的关键部件,由于其几何非对称,在发动机点火/熄火瞬间,SERN会产生较大的冷热态俯仰力矩差,影响飞行器的稳定性。现有解决方法主要是利用几何/气动调节方式,但都有不利影响。本文提出了基于膨胀度可控的SERN设计的新方法,将采用该方法得到的喷管模型B与基准喷管模型A进行了对比研究,并对模型B进行缩比冷流试验,试验与数值模拟结果吻合良好。研究结果表明:飞行马赫数为4.5时,模型B的推力系数比模型A仅仅下降了0.1%,而模型B比模型A的冷热态俯仰力矩差减小了80.49%;飞行马赫数为6.5时,模型B的推力系数比模型A不仅上升1.1%,同时模型B比模型A冷热态俯仰力矩差还下降12.73%,验证了设计思想的正确性,为提高SERN俯仰力矩性能提供了一种新的思路。

关键词：单边膨胀喷管俯仰力矩差膨胀程度风洞试验推力系数