Full-range equation for wave boundary layer thickness

Sana, Ahmad; Tanaka, Hitoshi

doi:10.1016/j.coastaleng.2007.01.011

Cited by 17 publications

(10 citation statements)

References 12 publications

(28 reference statements)

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“…Similarly, Figure 3 shows comparison of three equations for boundary layer thickness under rough turbulent condition. Again, the equation proposed by Sana and Tanaka [11] differs distinctly from other equations especially at higher / due to its larger power in Equation (12), which may cause underestimation of the boundary layer thickness for tsunami waves with a longer wave period. Similarly, Figure 3 shows comparison of three equations for boundary layer thickness under rough turbulent condition.…”

Section: Comparison Of Existing Formulaementioning

confidence: 86%

“…Figure 2 shows comparison among Equations ( 8)-( 10) for smooth turbulent condition. It is seen that Equations ( 8) and ( 10) have similar behavior, whereas the equation by Sana and Tanaka [11] has a smaller dependence on the Reynolds number. The line designated "Present study" represents a new equation proposed in this paper, which will be described later.…”

Section: Comparison Of Existing Formulaementioning

confidence: 90%

“…Wave boundary layer thickness has been formulated mainly using experimental results obtained in an oscillating tunnel [8][9][10][11]. It is well known that laminar wave boundary layer thickness is proportional to (νT) 1/2 (ν: kinematic viscosity, T: wave period) according to Stokes second problem [12].…”

Section: Introductionmentioning

confidence: 99%

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Improvement of the Full-Range Equation for Wave Boundary Layer Thickness

Tanaka¹,

Tinh²,

Sana

2020

JMSE

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In order to improve the accuracy of the original full-range equation for wave boundary layer thickness, with special reference to increasing its applicability to tsunami-scale waves, a theoretical investigation is carried out to derive a dimensionless expression which is valid under both smooth and rough turbulent regimes. A coefficient in the equation is determined through a comparison with k-ω model computation results for tsunami-waves along with laboratory scale oscillatory flow experiments. Thus, the improved full-range equation for wave boundary layer thickness enables us to cover a wide range of wave periods from wind-wave to tsunami.

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Section: Comparison Of Existing Formulaementioning

confidence: 86%

Section: Comparison Of Existing Formulaementioning

confidence: 90%

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Improvement of the Full-Range Equation for Wave Boundary Layer Thickness

Tanaka¹,

Tinh²,

Sana

2020

JMSE

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“…For computing wave boundary layer thickness under a shoaling tsunami, the full-range equation originally proposed by Sana and Tanaka [20,21] and recently modified by the authors [22] will be applied. The definition of wave boundary thickness proposed by Jensen et al [23] is used in this study, which is the height of overshooting at σt = 0 under the wave crest as defined in Figure 1b.…”

Section: Calculation Of Boundary Layer Thicknessmentioning

confidence: 99%

Transitional Behavior of a Flow Regime in Shoaling Tsunami Boundary Layers

Tanaka¹,

Tinh²,

Sana

2020

JMSE

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The transitional flow regime of the bottom boundary layer under hypothetical shoaling tsunamis is investigated in the entire region from the tsunami source to the shallow sea area. In order to calculate the shoaling process of a tsunami, an analytical method based on Green’s law and the linear long wave theory are employed, and flow regime criteria for the wave boundary layer proposed by one of the authors are applied. It is found that the bottom boundary layer in a tsunami source area is located in the laminar regime. Subsequently, transition occurs to the smooth turbulence during the shoaling process, with a transition from the smooth to the rough turbulent region in the shallow area. For precise evaluation of bottom friction acting on the sea bed and the resulting energy dissipation beneath the tsunami, it is highly necessary to include such transitional behavior in sea bottom boundary layers.

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“…and R is the Reynolds number based on the Stokes boundary layer thickness : U R 0m = In table 1 the regimes of motion are also shown, corresponding to the imposed test conditions to transitional regimes, being often encountered in shallow water systems (Sana and Tanaka, 2007). In details, disturbed laminar, where only small-amplitude perturbations appear superimposed to the oscillatory laminar flow, and intermittently turbulent, characterized by the burst of turbulence appears only during the decelerating phases of the cycle (Hino et al, 1983;Vittori and Verzicco, 1998) have been analyzed.…”

mentioning

confidence: 99%