[
    {
        "id": "authors:pawd6-2cg23",
        "collection": "authors",
        "collection_id": "pawd6-2cg23",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210312-151430797",
        "type": "article",
        "title": "Interactions between scales in wall turbulence: phase relationships, amplitude modulation and the importance of critical layers",
        "author": [
            {
                "family_name": "Jacobi",
                "given_name": "Ian",
                "orcid": "0000-0001-7377-8292",
                "clpid": "Jacobi-Ian"
            },
            {
                "family_name": "Chung",
                "given_name": "Daniel",
                "orcid": "0000-0003-3732-364X",
                "clpid": "Chung-Daniel"
            },
            {
                "family_name": "Duvvuri",
                "given_name": "Subrahmanyam",
                "orcid": "0000-0001-8082-1658",
                "clpid": "Duvvuri-Subrahmanyam"
            },
            {
                "family_name": "McKeon",
                "given_name": "Beverley J.",
                "orcid": "0000-0003-4220-1583",
                "clpid": "McKeon-B-J"
            }
        ],
        "abstract": "We present a framework for predicting the interactions between motion at a single scale and the underlying stress fluctuations in wall turbulence, derived from approximations to the Navier\u2013Stokes equations. The dynamical equations for an isolated scale and stress fluctuations at the same scale are obtained from a decomposition of the governing equations and formulated in terms of a transfer function between them. This transfer function is closely related to the direct correlation coefficient of Duvvuri & McKeon (J. Fluid Mech., vol. 767, 2015, R4), and approximately to the amplitude modulation coefficient described in Mathis et al. (J. Fluid Mech., vol. 628, 2009, pp. 311\u2013337), by consideration of interactions between triadically consistent scales. In light of the agreement between analysis and observations, the modelling approach is extended to make predictions concerning the relationship between very-large motions and small-scale stress in the logarithmic region of the mean velocity. Consistent with experiments, the model predicts that the zero-crossing height of the amplitude modulation statistic coincides with the wall-normal location of the very large-scale peak in the one-dimensional premultiplied spectrum of streamwise velocity fluctuations, the critical layer location for the very large-scale motion. Implications of fixed phase relationships between small-scale stresses and larger isolated scales for closure schemes are briefly discussed.",
        "doi": "10.1017/jfm.2020.770",
        "issn": "0022-1120",
        "publisher": "Cambridge University Press",
        "publication": "Journal of Fluid Mechanics",
        "publication_date": "2021-05-10",
        "volume": "914",
        "pages": "Art. No. A7"
    },
    {
        "id": "authors:b8yer-e6b53",
        "collection": "authors",
        "collection_id": "b8yer-e6b53",
        "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170213-124117937",
        "type": "article",
        "title": "Phase relations in a forced turbulent boundary layer: implications for modelling of high Reynolds number wall turbulence",
        "author": [
            {
                "family_name": "Duvvuri",
                "given_name": "Subrahmanyam",
                "orcid": "0000-0001-8082-1658",
                "clpid": "Duvvuri-Subrahmanyam"
            },
            {
                "family_name": "McKeon",
                "given_name": "Beverley",
                "orcid": "0000-0003-4220-1583",
                "clpid": "McKeon-B-J"
            }
        ],
        "abstract": "Phase relations between specific scales in a turbulent boundary layer are studied here by highlighting the associated nonlinear scale interactions in the flow. This is achieved through an experimental technique that allows for targeted forcing of the flow through the use of a dynamic wall perturbation. Two distinct large-scale modes with well-defined spatial and temporal wavenumbers were simultaneously forced in the boundary layer, and the resulting nonlinear response from their direct interactions was isolated from the turbulence signal for the study. This approach advances the traditional studies of large- and small-scale interactions in wall turbulence by focusing on the direct interactions between scales with triadic wavenumber consistency. The results are discussed in the context of modelling high Reynolds number wall turbulence.",
        "doi": "10.1098/rsta.2016.0080",
        "pmcid": "PMC5311448",
        "issn": "1364-503X",
        "publisher": "Royal Society of London",
        "publication": "Philosophical Transactions A: Mathematical, Physical and Engineering Sciences",
        "publication_date": "2017-03-13",
        "series_number": "2089",
        "volume": "375",
        "issue": "2089",
        "pages": "Art. No. 20160080"
    }
]