湍流边界层多尺度结构间歇性检测和控制的实验研究
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摘要
为了解壁面局部加热对湍流边界层多尺度流动结构的影响,以便对壁湍流多尺度相干结构进行控制,在平板上布置一组固定展向间距的沿流向的平行加热丝,用IFA300热线风速仪以高于对应最小湍流时间尺度的分辨率,精细测量了平板湍流边界层在加热前后各法向位置的湍流流向速度的时间序列信号。对比研究了平板湍流边界层,加热前后各法向位置湍流多尺度相干结构的能量分布、发生概率、相对强度等统计性质的变化规律,分析了壁面平行流向涡控制湍流多尺度结构最终达到减阻效果的机理。
同时计算了耗散尺度、泰勒尺度、剪切尺度和积分尺度等特征量,并给出它们沿平板湍流边界层法向位置的变化规律。用子波分析对湍流脉动速度信号进行多尺度分解,用自相关法得到不同尺度湍涡的空间长度,研究了子波分析的尺度参数a与耗散尺度、泰勒尺度、剪切尺度和积分尺度的对应关系。
在研究过程中,验证了基于湍流结构局部平均概念的速度结构函数与Harr子波变换的一致性。提出了基于子波系数的瞬时强度因子、瞬时平坦因子的概念,及检测多尺度相干结构的准则。提取了湍流边界层中多尺度相干结构的条件平均波形, 研究了多尺度相干结构猝发的动力学过程。实验发现,提取出的各尺度相干结构具有一定的相似性,它们是湍流边界层产生间歇性和奇异标度律的原因。
In order to learn about the effect of local heating on the wall affecting on multi-scale structures in turbulent boundary layer ,a group of longitudinal heating wires are laid on the flat-plate. Before and after heating up ,the longitudinal velocity time sequence at different vertical locations in a flat-plate turbulent boundary layer are finely measured by IFA300 with resolution higher than Kolmogorov scale. A comparative study has been performed on the statistical characteristics such as energy distribution, occurring probability and relative intension of multi-scale coherent eddy structure at different Reynold quantities and vertical locations in a flat-plate turbulent boundary layer before and after heating up.An analysis has been carried out to reveal that turbulent multi-scale structures are controlled by wall longitudinal eddy and therefore the friction is reduced .
Dissipative ,Taylor , shear and integral scale are calculated ,and the relationship between them and vertical locations in turbulent boundary layer are obtained.The turbulent fluctuation velocity signals are analyzed for multi-scale structure decomposition by wavelet transform.Space length of multi-scale eddy structure are gained by self-correlation method.Finaly,the relationship between scale parameter of wavelet transform and dissipative ,Taylor, shear and integral scale are studied.
Through the present study, the velocity structure function based on locally averaged turbulent structure is proved to agree with Harr wavelet transform.The new concept of instantaneous intensity factor and instantaneous flatness factor based on wavelet coefficients together with sampling schemes for multi-scale coherent eddy structures are represented in this paper.Moreover phased-average evolution shapes for multi-scale coherent eddy structures in turbulent boundary layer are extracted and the dynamic course of the burst of multi-scale coherent eddy structures is researched. The experiment study reveals that the coherent eddy structure picked up at different scales share similar shape and they are responsible for the intermittency and the anomalous scaling law in the turbulent boundary layer .
同时计算了耗散尺度、泰勒尺度、剪切尺度和积分尺度等特征量,并给出它们沿平板湍流边界层法向位置的变化规律。用子波分析对湍流脉动速度信号进行多尺度分解,用自相关法得到不同尺度湍涡的空间长度,研究了子波分析的尺度参数a与耗散尺度、泰勒尺度、剪切尺度和积分尺度的对应关系。
在研究过程中,验证了基于湍流结构局部平均概念的速度结构函数与Harr子波变换的一致性。提出了基于子波系数的瞬时强度因子、瞬时平坦因子的概念,及检测多尺度相干结构的准则。提取了湍流边界层中多尺度相干结构的条件平均波形, 研究了多尺度相干结构猝发的动力学过程。实验发现,提取出的各尺度相干结构具有一定的相似性,它们是湍流边界层产生间歇性和奇异标度律的原因。
In order to learn about the effect of local heating on the wall affecting on multi-scale structures in turbulent boundary layer ,a group of longitudinal heating wires are laid on the flat-plate. Before and after heating up ,the longitudinal velocity time sequence at different vertical locations in a flat-plate turbulent boundary layer are finely measured by IFA300 with resolution higher than Kolmogorov scale. A comparative study has been performed on the statistical characteristics such as energy distribution, occurring probability and relative intension of multi-scale coherent eddy structure at different Reynold quantities and vertical locations in a flat-plate turbulent boundary layer before and after heating up.An analysis has been carried out to reveal that turbulent multi-scale structures are controlled by wall longitudinal eddy and therefore the friction is reduced .
Dissipative ,Taylor , shear and integral scale are calculated ,and the relationship between them and vertical locations in turbulent boundary layer are obtained.The turbulent fluctuation velocity signals are analyzed for multi-scale structure decomposition by wavelet transform.Space length of multi-scale eddy structure are gained by self-correlation method.Finaly,the relationship between scale parameter of wavelet transform and dissipative ,Taylor, shear and integral scale are studied.
Through the present study, the velocity structure function based on locally averaged turbulent structure is proved to agree with Harr wavelet transform.The new concept of instantaneous intensity factor and instantaneous flatness factor based on wavelet coefficients together with sampling schemes for multi-scale coherent eddy structures are represented in this paper.Moreover phased-average evolution shapes for multi-scale coherent eddy structures in turbulent boundary layer are extracted and the dynamic course of the burst of multi-scale coherent eddy structures is researched. The experiment study reveals that the coherent eddy structure picked up at different scales share similar shape and they are responsible for the intermittency and the anomalous scaling law in the turbulent boundary layer .
引文
[1]Tennekes H,Lumley J.L. A First Course in Turbulence [M], M.I.T.Press Cambridge,Massachussetts and London,England,1972.
[2]L.Landau,E.Lifshitz,Mecanique des Fluids,Mir,Moscow(1973).
[3] G Ruiz Chavarria, S Ciliberto, C Baudet, E Leveque, Scaling properties of the streamwise component of velocity in a turbulent boundary layer [J]. Physica D, 2000, 141: 183~198.
[4]欣茨著.湍流.北京:科学出版社,1987。
[5]张兆顺著.湍流.北京:国防工业出版社,2002。
[6]是勋刚主编.湍流.天津:天津大学出版社,1994。
[7] Farge M., Wavelet transforms and their applications to turbulence [J], Annu. Review Fluid Mech.,1992,24:395-457.
[8] Marie Farge, Nicholas Kevlahan, Valerie Perrier, Eric Goirand, Wavelet and turbulence [J], Proceedings of the IEEE, 1996, Vol.84, No. 4: 639~669.
[9] Marie Farge, Kai Schneider, Coherent vortex simulation (CVS), A semi-deterministic turbulence model using wavelet [J], Flow, Turbulence and Combustion, 2001, Vol.66: 393-426.
[10] Shu Wei, Jiang Nan, Eddy Scale Analysis in Turbulence[J], Acta Aerodynamica Sinica, 2000, 18, supplement: 89~95 (in Chinese).
舒玮、姜楠,湍流中涡的尺度分析[J],空气动力学报,2000,18卷,增刊:89~95。
[11] R.Camussi, G.Guj, Orthonormal wavelet decomposition of turbulent flows: intermittency and coherent structures [J], J. Fluid Mech. (1997), vol. 348. pp 177-199.
[12] Kolmogorov A N, Dissipation of energy in the locally isotropic turbulence [J]. Dokl Akad Nauk SSSR, 1941, 32(1): 19~21.
[13] Kolmogorov A N, A refinement of previous hypothesis concerning the local structure of turbulence in a viscous incompressible fluid at high Reynolds number [J]. J Fluid Mech., 1962, 13(1): 82~85.
[14]Kline S J, Reynolds W C, Schraub F H, Runstadler P W, The structure of turbulent boundary layer [J], J Fluid Mech., 1967, 30: 741~774.
[15]Smith C R, Metzler S P, The characteristics of low speed streaks in the near wall region of a turbulent boundary layer [J], J. Fluid Mech., 1983, 129: 27~54.
[16]姜楠,王玉春,壁湍流温度扩展的自相似性及其层次结构模型,实验力学,2001,16(4):366-371。
[17]姜楠,王玉春,壁湍流扩展的自相似标度律的实验研究,实验力学,2002,17(1):28-34。
[18]姜楠,子波变换在实验流体力学中的应用,流体力学实验与测量,1997,11(1):12-19。
[19]姜楠,王玉春,黄章峰,壁湍流标度律的实验研究,空气动力学报,2001,19(2):241-246。
[20]姜楠,舒玮,壁湍流相干结构的辨识,实验力学,1996,11(4):494-500
[21]姜楠,舒玮,王振东,子波分析辨识壁湍流猝发事件的能量最大准则,力学 学报,1997,29(3):406-412
[22]姜楠,王玉春,舒玮等,壁面加热湍流标度律的实验研究,空气动力学报,2001,19(3):354-363。
[23]姜楠,王玉春,王振东等,壁面加热边界条件对湍流扩展的自相似性的影响,实验力学,2001,16(3):256~263。
[2]L.Landau,E.Lifshitz,Mecanique des Fluids,Mir,Moscow(1973).
[3] G Ruiz Chavarria, S Ciliberto, C Baudet, E Leveque, Scaling properties of the streamwise component of velocity in a turbulent boundary layer [J]. Physica D, 2000, 141: 183~198.
[4]欣茨著.湍流.北京:科学出版社,1987。
[5]张兆顺著.湍流.北京:国防工业出版社,2002。
[6]是勋刚主编.湍流.天津:天津大学出版社,1994。
[7] Farge M., Wavelet transforms and their applications to turbulence [J], Annu. Review Fluid Mech.,1992,24:395-457.
[8] Marie Farge, Nicholas Kevlahan, Valerie Perrier, Eric Goirand, Wavelet and turbulence [J], Proceedings of the IEEE, 1996, Vol.84, No. 4: 639~669.
[9] Marie Farge, Kai Schneider, Coherent vortex simulation (CVS), A semi-deterministic turbulence model using wavelet [J], Flow, Turbulence and Combustion, 2001, Vol.66: 393-426.
[10] Shu Wei, Jiang Nan, Eddy Scale Analysis in Turbulence[J], Acta Aerodynamica Sinica, 2000, 18, supplement: 89~95 (in Chinese).
舒玮、姜楠,湍流中涡的尺度分析[J],空气动力学报,2000,18卷,增刊:89~95。
[11] R.Camussi, G.Guj, Orthonormal wavelet decomposition of turbulent flows: intermittency and coherent structures [J], J. Fluid Mech. (1997), vol. 348. pp 177-199.
[12] Kolmogorov A N, Dissipation of energy in the locally isotropic turbulence [J]. Dokl Akad Nauk SSSR, 1941, 32(1): 19~21.
[13] Kolmogorov A N, A refinement of previous hypothesis concerning the local structure of turbulence in a viscous incompressible fluid at high Reynolds number [J]. J Fluid Mech., 1962, 13(1): 82~85.
[14]Kline S J, Reynolds W C, Schraub F H, Runstadler P W, The structure of turbulent boundary layer [J], J Fluid Mech., 1967, 30: 741~774.
[15]Smith C R, Metzler S P, The characteristics of low speed streaks in the near wall region of a turbulent boundary layer [J], J. Fluid Mech., 1983, 129: 27~54.
[16]姜楠,王玉春,壁湍流温度扩展的自相似性及其层次结构模型,实验力学,2001,16(4):366-371。
[17]姜楠,王玉春,壁湍流扩展的自相似标度律的实验研究,实验力学,2002,17(1):28-34。
[18]姜楠,子波变换在实验流体力学中的应用,流体力学实验与测量,1997,11(1):12-19。
[19]姜楠,王玉春,黄章峰,壁湍流标度律的实验研究,空气动力学报,2001,19(2):241-246。
[20]姜楠,舒玮,壁湍流相干结构的辨识,实验力学,1996,11(4):494-500
[21]姜楠,舒玮,王振东,子波分析辨识壁湍流猝发事件的能量最大准则,力学 学报,1997,29(3):406-412
[22]姜楠,王玉春,舒玮等,壁面加热湍流标度律的实验研究,空气动力学报,2001,19(3):354-363。
[23]姜楠,王玉春,王振东等,壁面加热边界条件对湍流扩展的自相似性的影响,实验力学,2001,16(3):256~263。