What is it about?
In this study, we introduce a new analytical framework for predicting how friction and boundary layers block airflow inside pipes and ducts. This phenomenon, known as Sanal flow choking, occurs locally due to boundary layer growth that narrows the flow path—similar to a throat in a nozzle—causing a sudden restriction in flow when a critical pressure ratio is reached. Unlike traditional models, our theory applies universally—from nano- to industrial-scale systems—and satisfies all physical conservation laws. We developed closed-form mathematical models to calculate how much of a pipe’s cross-section is blocked at the exact point where choking happens. These models are free from empirical approximations and numerical errors, making them ideal for verifying and calibrating computational fluid dynamics (CFD) codes. Importantly, we show that Sanal flow choking is not just a theoretical idea—it can predict where shock waves, detonation, or pressure surges may happen in real-world systems such as pipelines, rocket motors, or even biological vessels under stress. The benchmark data we provide are crucial for researchers developing fluid simulation tools across aerospace, energy, and biomedical engineering.
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Why is it important?
This work presents the first universal, closed-form models to predict flow blockage and friction at the exact point of choking due to boundary layer growth—a phenomenon known as Sanal flow choking. Unlike traditional models, it applies across scales and flow types without relying on empirical data or numerical discretization. The benchmark data enable accurate verification of CFD codes, making it a timely and essential contribution for advancing simulations in aerospace, energy, and biomedical systems where shock waves or detonation risks must be reliably predicted.
Perspectives
From my perspective, this work represents a breakthrough in fluid dynamics modeling. For years, code verification in compressible viscous flows lacked a universal, error-free reference. By deriving closed-form solutions rooted in conservation laws, we’ve filled that gap with reliable benchmark data. One of the most compelling insights is that Sanal flow choking is a localized fluid flow phenomenon where all conservation laws—mass, momentum, and energy—are simultaneously satisfied. This makes the boundary layer–induced blockage factor at the choking point a robust benchmark for code verification and calibration, regardless of whether the overall flow is laminar, turbulent, adiabatic, or diabatic. I’m particularly inspired by the fact that this model bridges theoretical rigor and real-world relevance—helping predict not just industrial flow choking but also physiological events like vascular blockages and shock wave formation. I believe this framework will empower both researchers and engineers to approach complex flow problems with greater confidence and clarity.
Dr. SANAL KUMAR VR
Amity University
Read the Original
This page is a summary of: Universal benchmark data of the three-dimensional boundary layer blockage and average friction coefficient for in silico code verification, Physics of Fluids, April 2022, American Institute of Physics,
DOI: 10.1063/5.0086638.
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