# Magnetohydrodynamics Flow Past a Moving Vertical Thin Needle in a Nanofluid with Stability Analysis
It is considered \"thin\" when its thicknesses do not exceed the boundary on it or smaller. The consideration of the thin needle in the boundary layer flow is first studied by [PERSON] [10]. It is important to know that the motion of the thin needle in the flow disturbs the free stream direction and this phenomenon is the main focus to measure the velocity and temperature profiles of the flow field in experimental studies. The usage of the thin needle is an increasingly important aspect of medicine and engineering industries. Some examples are the blood flow problem, transportation, hot wire anemometer for measuring wind's velocity, lubrication and coating of wires. Over the last few decades, the consideration on the topic of thin needle has gained a vast number of researchers due to its contribution to the industries. Extension to [PERSON] [10] work, [PERSON] and [PERSON] [11] considered the forced heat transfer over a thin needle in viscous fluid. The problem of steady laminar forced convection flow over a non-isothermal thin needle is analytically studied by [PERSON] and [PERSON] [12]. Since the pioneering work of [PERSON] [10], the problems related to the thin needle in viscous fluid have increased greatly in recent years [13; 14; 15; 16]. Due to the existence of nanofluid that enhances the thermal conductivity of the base fluid, some authors used this as an opportunity to perform the boundary layer flow of a thin needle immersed in nanofluid. [PERSON] and [PERSON] [17] presented the classical problem of forced convection flow and heat transfer past a needle with variable wall temperature. On the other hand, [PERSON] et al. [18] analyzed the effect of variable surface heat flux on the heat transfer phenomenon by using water-carbon nanofluid. [PERSON] et al. [19] and [PERSON] et al. [20] investigated the flow and heat transfer past a moving thin needle with the magnetohydrodynamic radiative nanofluid, and stability analysis, respectively. Moreover, [PERSON] et al. [21] attempted to consider the Buongiorno nanofluid flow past a moving thin needle. However, all the studies mentioned above are restricted to the horizontal surface of the needle. It has been found in the existing literature that the study of the vertical thin needle is less concerned. [PERSON] et al. [22] are the first authors who studied such problems by considering the mixed convection flow past a stationary thin needle in nanofluid. Finally, we mention also the recently published paper by [PERSON] et al. [23] on the stability analysis of mixed convection flow towards a moving thin needle in a nanofluid. In fluid mechanics, many researches and development processes are being done for enhancing heat transport properties of conventional heat transfer fluid. The thermal conductivity of heat transfer fluid plays a major role in the development of energy efficient heat transfer application. The conventional heat transfer fluids such as water, ethylene glycol, oil and mixtures have met their thermal performance limitations. To overcome these limitations and satisfy the cooling process requirement, [PERSON] [24] introduced a new heat transfer fluid, known as nanofluid. Nanofluid is a homogenous mixture of the base fluid and nanoparticle with 10-100 nm diameter. Nanofluid is said to be the promising way for enhancing the performance of heat transfer in fluid and it is expected to have superior thermal conductivity compared to base fluid. Nanoparticles consist of different materials, for example, ceramics, metals, alloys, semiconductors, nanotubes, and composite particles. For almost two decades, nanofluid has been used as advanced heat transfer fluid, especially in power generation, transportation, electronics cooling, chemical production and biomedical industries [25; 26; 27]. Physically, the tiny size of the nanoelements leads to a better suspension stability, ability to flow smoothly without clogging the system and providing enhanced thermal and physical properties.